#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int t;
	cin >> t;
	while (t--) {
		int a, b;
		cin >> a >> b;
		if (a % b == 0) cout << 0 << endl;
		else cout << b - a % b << endl;
	}
	
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

#define forn(i, n) for (int i = 0; i < int(n); i++)

int main() {
    int t;
    cin >> t;
    forn(tt, t) {
        int n, k;
        cin >> n >> k;
        string s(n, 'a');
        for (int i = n - 2; i >= 0; i--) {
            if (k <= (n - i - 1)) {
                s[i] = 'b';
                s[n - k] = 'b';
                cout << s << endl;
                break;
            }
            k -= (n - i - 1);
        }
    }
}

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int t;
	cin >> t;
	while (t--) {
		int n;
		string x;
		cin >> n >> x;
		string a(n, '0'), b(n, '0');
		for (int i = 0; i < n; ++i) {
			if (x[i] == '1') {
				a[i] = '1';
				b[i] = '0';
				for (int j = i + 1; j < n; ++j) {
					b[j] = x[j];
				}
				break;
			} else {
				a[i] = b[i] = '0' + (x[i] - '0') / 2;
			}
		}
		cout << a << endl << b << endl;
	}
	
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

int solve() {
	int n;
	cin >> n;
	vector<int> a(n);
	for (int i = 0; i < n; ++i) {
		cin >> a[i];
	}
	
	if (count(a.begin(), a.end(), a[0]) == n) {
		cout << 1 << endl;
		for (int i = 0; i < n; ++i) {
			cout << 1 << " ";
		}
		cout << endl;
		return 0;
	}
	
	if (n % 2 == 0) {
		cout << 2 << endl;
		for (int i = 0; i < n; ++i) {
			cout << i % 2 + 1 << " ";
		}
		cout << endl;
		return 0;
	}
	
	for (int i = 0; i < n; ++i) {
		if (a[i] == a[(i + 1) % n]) {
			vector<int> ans(n);
			for (int j = 0, pos = i + 1; pos < n; ++pos, j ^= 1) {
				ans[pos] = j + 1;
			}
			for (int j = 0, pos = i; pos >= 0; --pos, j ^= 1) {
				ans[pos] = j + 1;
			}
			cout << 2 << endl;
			for (int pos = 0; pos < n; ++pos) {
				cout << ans[pos] << " ";
			}
			cout << endl;
			return 0;
		}
	}
	
	cout << 3 << endl;
	for (int i = 0; i < n - 1; ++i) {
		cout << i % 2 + 1 << " ";
	}
	cout << 3 << endl;
    return 0;    
}

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif

int q;
cin >> q;
for (int qq = 0; qq < q; qq++) {
    solve();
}

	return 0;
}

#include <bits/stdc++.h>

using namespace std;

int T;
vector<int> p, d;
vector<int> tin, tout;
vector<vector<int>> g;

void dfs(int v, int par = -1, int dep = 0) {
	p[v] = par;
	d[v] = dep;
	tin[v] = T++;
	for (auto to : g[v]) {
		if (to == par) continue;
		dfs(to, v, dep + 1);
	}
	tout[v] = T++;
}

bool isAnc(int v, int u) {
	return tin[v] <= tin[u] && tout[u] <= tout[v];
}

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int n, m;
	cin >> n >> m;
	T = 0;
	p = d = vector<int>(n);
	tin = tout = vector<int>(n);
	g = vector<vector<int>>(n);
	for (int i = 0; i < n - 1; ++i) {
		int x, y;
		cin >> x >> y;
		--x, --y;
		g[x].push_back(y);
		g[y].push_back(x);
	}
	dfs(0);
	
	for (int i = 0; i < m; ++i) {
		int k;
		cin >> k;
		vector<int> v(k);
		for (auto &it : v) {
			cin >> it;
			--it;
		}
		
		int u = v[0];
		for (auto it : v) if (d[u] < d[it]) u = it;
		for (auto &it : v) {
			if (it == u) continue;
			if (p[it] != -1) it = p[it];
		}
		bool ok = true;
		for (auto it : v) ok &= isAnc(it, u);
		if (ok) cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

const long long INF64 = 1e18;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int n, k;
	cin >> n >> k;
	vector<int> a(n);
	for (auto &it : a) cin >> it;
	
	sort(a.begin(), a.end());
	vector<pair<int, int>> cnt;
	for (auto it : a) {
		if (cnt.empty() || cnt.back().first != it) {
			cnt.push_back({it, 1});
		} else {
			++cnt.back().second;
		}
	}
	vector<long long> prefsum, sufsum;
	vector<int> prefcnt, sufcnt; 
	for (int i = 0; i < int(cnt.size()); ++i) {
		long long cursum = cnt[i].first * 1ll * cnt[i].second;
		int curcnt = cnt[i].second;
		if (prefsum.empty()) {
			prefsum.push_back(cursum);
			prefcnt.push_back(curcnt);
		} else {
			prefsum.push_back(prefsum.back() + cursum);
			prefcnt.push_back(prefcnt.back() + curcnt);
		}
	}
	for (int i = int(cnt.size()) - 1; i >= 0; --i) {
		long long cursum = cnt[i].first * 1ll * cnt[i].second;
		int curcnt = cnt[i].second;
		if (sufsum.empty()) {
			sufsum.push_back(cursum);
			sufcnt.push_back(curcnt);
		} else {
			sufsum.push_back(sufsum.back() + cursum);
			sufcnt.push_back(sufcnt.back() + curcnt);
		}
	}
	reverse(sufsum.begin(), sufsum.end());
	reverse(sufcnt.begin(), sufcnt.end());
	
	long long ans = INF64;
	for (int i = 0; i < int(cnt.size()); ++i) {
		int cur = max(0, k - cnt[i].second);
		
		int needl = 0;
		if (i > 0) needl = min(cur, prefcnt[i - 1]);
		int needr = max(0, cur - needl);
		long long res = 0;
		if (i > 0 && needl > 0) {
			res += prefcnt[i - 1] * 1ll * (cnt[i].first - 1) - prefsum[i - 1];
			res += needl;
		}
		if (i + 1 < int(cnt.size()) && needr > 0) {
			res += sufsum[i + 1] - sufcnt[i + 1] * 1ll * (cnt[i].first + 1);
			res += needr;
		}
		ans = min(ans, res);
		
		needr = 0;
		if (i + 1 < int(cnt.size())) needr = min(cur, sufcnt[i + 1]);
		needl = max(0, cur - needr);
		res = 0;
		if (i > 0 && needl > 0) {
			res += prefcnt[i - 1] * 1ll * (cnt[i].first - 1) - prefsum[i - 1];
			res += needl;
		}
		if (i + 1 < int(cnt.size()) && needr > 0) {
			res += sufsum[i + 1] - sufcnt[i + 1] * 1ll * (cnt[i].first + 1);
			res += needr;
		}
		ans = min(ans, res);
	}
	
	cout << ans << endl;
	
	return 0;
}