def read():
    return int(input())
def read_list():
    return [int(i) for i in input().split()]

test_count = read()
for test in range(test_count):
	n, m = read_list();

	g = [[] for i in range(n+1)]
	mark = [False] * (n+1)

	for i in range(m):
		u, v = read_list()
		g[u].append(v)
		g[v].append(u)

	def dfs(node):
		if mark[node]:
			return
		mark[node] = True
		for i in g[node]:
			dfs(i)


	dfs(1)

	if mark[n]:
		print("yes")
	else:
		print("no")

#include "cstdlib"
#include "cstring"
#include "cmath"
#include "iostream"
#include "stack"
#include "vector"
#include "array"
#include "queue"
#include "algorithm"
#include "map"
#include "set"
#include "unordered_map"
#include "unordered_set"
#include "numeric"
#include "string"
#include "iomanip"
#include "climits"
#include "functional"
#include "cctype"

using namespace std; 
#define array_size(a) (sizeof(a)/sizeof(a[0]))
#define rep(name, start, end) for (int name=(start); name<=(end); name++)
#define repr(name, start, end) for (int name=(start); name>=(end); name--)
#define all(a) a.begin(), a.end()
using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
#define MOD 1000000007
// #define MOD 998244353
#define NL '\n'
#define nl '\n'

template<typename T> 
using min_heap = priority_queue<T, vector<T>, greater<T>>;

template<typename T> 
using max_heap = priority_queue<T>;

template<typename T> 
using matrix = vector<vector<T>>;

template<typename T> 
void _dbg(const char* name, T cont) {
	cerr << "#" << name << " = {"; 
	int n = cont.size();
	int idx = 0;
	for (auto i: cont) {
		cerr << i;
		if (++idx < n) {
			cerr << ", ";
		}
	}
	cerr << "}" << nl;
}


#ifndef ONLINE_JUDGE
#define dbg(x) _dbg(#x, x) 
#else 
#define dbg(x)
#endif

matrix<int>  g;
vector<bool> v;

void dfs(int node) {
	if (v[node]) return;
	v[node] = true;
	for (int i: g[node]) {
		dfs(i);
	}
}

void solve() {
	int n, m; cin >> n >> m;
	g.resize(n+1);
	v.resize(n+1);
	rep (i, 1, m) {
		int a, b; cin >> a >> b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	dfs(1);
	if (v[n]) {
		cout << "YES" << nl;
	} else {
		cout << "NO" << nl;
	}
	g.clear();
	v.clear();
}	
	

int main() {
	#ifndef ONLINE_JUDGE 
		freopen("input.txt", "r", stdin);
		// freopen("output.txt", "w", stdout);
	#else
		ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	#endif

	int t=1;
	cin >> t;
	rep(test, 1, t)  {
		solve();
	}
}

def read():
    return int(input())
def read_list():
    return [int(i) for i in input().split()]
 
test_count = read()
for test in range(test_count):
	n, m = read_list();
 
	g = [[] for i in range(n+1)]
	mark = [False] * (n+1)
 
	for i in range(m):
		u, v = read_list()
		g[u].append(v)
		g[v].append(u)
 
	def dfs(node):
		if mark[node]:
			return
		mark[node] = True
		for i in g[node]:
			dfs(i)
 
	result = 0
	for i in range(1, n+1):
		if not mark[i]:
			dfs(i)
			result += 1
	print(result)
 

#include "cstdlib"
#include "cstring"
#include "cmath"
#include "iostream"
#include "stack"
#include "vector"
#include "array"
#include "queue"
#include "algorithm"
#include "map"
#include "set"
#include "unordered_map"
#include "unordered_set"
#include "numeric"
#include "string"
#include "iomanip"
#include "climits"
#include "functional"
#include "cctype"
 
using namespace std; 
#define array_size(a) (sizeof(a)/sizeof(a[0]))
#define rep(name, start, end) for (int name=(start); name<=(end); name++)
#define repr(name, start, end) for (int name=(start); name>=(end); name--)
#define all(a) a.begin(), a.end()
using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
#define MOD 1000000007
// #define MOD 998244353
#define NL '\n'
#define nl '\n'
 
template<typename T> 
using min_heap = priority_queue<T, vector<T>, greater<T>>;
 
template<typename T> 
using max_heap = priority_queue<T>;
 
template<typename T> 
using matrix = vector<vector<T>>;
 
template<typename T> 
void _dbg(const char* name, T cont) {
	cerr << "#" << name << " = {"; 
	int n = cont.size();
	int idx = 0;
	for (auto i: cont) {
		cerr << i;
		if (++idx < n) {
			cerr << ", ";
		}
	}
	cerr << "}" << nl;
}
 
 
#ifndef ONLINE_JUDGE
#define dbg(x) _dbg(#x, x) 
#else 
#define dbg(x)
#endif
 
matrix<int>  g;
vector<bool> v;
 
void dfs(int node) {
	if (v[node]) return;
	v[node] = true;
	for (int i: g[node]) {
		dfs(i);
	}
}
 
void solve() {
	int n, m; cin >> n >> m;
	g.resize(n+1);
	v.resize(n+1);
	rep (i, 1, m) {
		int a, b; cin >> a >> b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	int result = 0;
	rep (i, 1, n) {
		if (!v[i]) {
			dfs(i);
			result++;
		}
	}
	cout << result << nl;
	g.clear();
	v.clear();
}	
	
 
int main() {
	#ifndef ONLINE_JUDGE 
		freopen("input.txt", "r", stdin);
		// freopen("output.txt", "w", stdout);
	#else
		ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	#endif
 
	int t=1;
	cin >> t;
	rep(test, 1, t)  {
		solve();
	}
}

def read():
    return int(input())
def read_list():
    return [int(i) for i in input().split()]
 
test_count = read()
for test in range(test_count):
	n, m = read_list();
 
	g = [input() for i in range(n)]
	mark = [[False] * m for i in range(n)]
 
	def dfs(i, j):
		if g[i][j] == '#' or mark[i][j]:
			return
		mark[i][j] = True
		dfs(i+1, j)
		dfs(i-1, j)
		dfs(i, j+1)
		dfs(i, j-1)
 
	result = 0
	for i in range(n):
		for j in range(m):
			if not mark[i][j] and g[i][j] == '.':
				dfs(i, j)
				result += 1
	print(result)
 

#include "cstdlib"
#include "cstring"
#include "cmath"
#include "iostream"
#include "stack"
#include "vector"
#include "array"
#include "queue"
#include "algorithm"
#include "map"
#include "set"
#include "unordered_map"
#include "unordered_set"
#include "numeric"
#include "string"
#include "iomanip"
#include "climits"
#include "functional"
#include "cctype"
 
using namespace std; 
#define array_size(a) (sizeof(a)/sizeof(a[0]))
#define rep(name, start, end) for (int name=(start); name<=(end); name++)
#define repr(name, start, end) for (int name=(start); name>=(end); name--)
#define all(a) a.begin(), a.end()
using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
#define MOD 1000000007
// #define MOD 998244353
#define NL '\n'
#define nl '\n'
 
template<typename T> 
using min_heap = priority_queue<T, vector<T>, greater<T>>;
 
template<typename T> 
using max_heap = priority_queue<T>;
 
template<typename T> 
using matrix = vector<vector<T>>;
 
template<typename T> 
void _dbg(const char* name, T cont) {
	cerr << "#" << name << " = {"; 
	int n = cont.size();
	int idx = 0;
	for (auto i: cont) {
		cerr << i;
		if (++idx < n) {
			cerr << ", ";
		}
	}
	cerr << "}" << nl;
}
 
 
#ifndef ONLINE_JUDGE
#define dbg(x) _dbg(#x, x) 
#else 
#define dbg(x)
#endif
 
vector<string>  g;
vector<vector<bool>> v;
 
void dfs(int i, int j) {
	if (g[i][j] == '#' || v[i][j]) return;
	v[i][j] = true;
 
	dfs(i,j+1);
	dfs(i,j-1);
	dfs(i+1,j);
	dfs(i-1,j);
}
 
void solve() {
	int n, m; cin >> n >> m;
	g.resize(n);
	v.resize(n, vector<bool>(m));
	rep (i, 0, n-1) {
		cin >> g[i];
	}
	int result = 0;
	rep (i, 0, n-1) {
		rep (j, 0, m-1) {
			if (!v[i][j] && g[i][j] == '.') {
				dfs(i, j);
				result++;
			}
		}
	}
	cout << result << nl;
	g.clear();
	v.clear();
}	
	
 
int main() {
	#ifndef ONLINE_JUDGE 
		freopen("input.txt", "r", stdin);
		// freopen("output.txt", "w", stdout);
	#else
		ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	#endif
 
	int t=1;
	cin >> t;
	rep(test, 1, t)  {
		solve();
	}
}