#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    string s;
    cin >> s;
    int index = 0;
    int gap = 1;
    while (index < n)
        cout << s[index], index += gap, gap++;
}

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int n;
	cin >> n;
	vector<int> a(n);
	for (int i = 0; i < n; ++i) {
		cin >> a[i];
	}
	sort(a.begin(), a.end());
	
	cout << min(a[n - 2] - a[0], a[n - 1] - a[1]) << endl;
	
	return 0;
}

#include<bits/stdc++.h>

using namespace std;

int main()
{
	int n, k;
	cin >> n >> k;
	map<int, int> ans;
	queue<int> q;
	for(int i = 0; i <= 30; i++)
		if(n & (1 << i))
		{
			if(i > 0) q.push(1 << i);
			ans[1 << i]++;
		}
	if(int(ans.size()) > k)
	{
		puts("NO");
		return 0;
	}
	int cnt = ans.size();
	while(cnt < k && !q.empty())
	{
		int z = q.front();
		q.pop();
		ans[z]--;
		ans[z / 2] += 2;
		if(z / 2 > 1)
		{
			q.push(z / 2);
			q.push(z / 2);
		}
		cnt++;
	}
	if(cnt < k)
	{
		puts("NO");
		return 0;
	}
	puts("YES");
	for(auto x : ans)
		for(int i = 0; i < x.second; i++)
			printf("%d ", x.first);
	puts("");
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

int n;
vector<vector<int>> a;

void check(int l, int r) {
	vector<int> ans;
	for (int i = 0; i < n; ++i) {
		int nxt = -1;
		if (a[l][0] == r) {
			nxt = a[l][1];
		} else if (a[l][1] == r) {
			nxt = a[l][0];
		} else {
			return;
		}
		ans.push_back(nxt);
		l = r;
		r = nxt;
	}
	for (auto it : ans) {
		cout << it + 1 << " ";
	}
	cout << endl;
	exit(0);
}

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	cin >> n;
	a = vector<vector<int>> (n, vector<int>(2));
	for (int i = 0; i < n; ++i) {
		cin >> a[i][0] >> a[i][1];
		--a[i][0];
		--a[i][1];
	}
	
	check(0, a[0][0]);
	check(0, a[0][1]);
	
	assert(false);
	
	return 0;
}

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int n;
	string s;
	cin >> n >> s;
	
	string rs(s.rbegin(), s.rend());
	for (int i = 0; i < n; ++i) {
		if (rs[i] == '(') {
			rs[i] = ')';
		} else {
			rs[i] = '(';
		}
	}
	
	vector<int> pref(n + 1), suf(n + 1);
	vector<bool> okp(n + 1), oks(n + 1);
	okp[0] = oks[n] = true;
	for (int i = 0; i < n; ++i) {
		pref[i + 1] = pref[i] + (s[i] == '(' ? +1 : -1);
		okp[i + 1] = okp[i] & (pref[i + 1] >= 0);
		suf[n - i - 1] = suf[n - i] + (rs[i] == '(' ? +1 : -1);
		oks[n - i - 1] = oks[n - i] & (suf[n - i - 1] >= 0);
	}
	
	int ans = 0;
	for (int i = 0; i < n; ++i) {
		if (!okp[i] || !oks[i + 1]) {
			continue;
		}
		if (s[i] == '(') {
			if (pref[i] > 0 && pref[i] - 1 - suf[i + 1] == 0) {
				++ans;
			}
		} else {
			if (pref[i] + 1 - suf[i + 1] == 0) {
				++ans;
			}
		}
	}
	
	cout << ans << endl;
	
	return 0;
}

#include<bits/stdc++.h>

using namespace std;

#define x first
#define y second
#define mp make_pair

typedef pair<long long, pair<int, int> > edge;

const int N = 200043;

int p[N];
long long a[N];

int get_leader(int x)
{
	return (x == p[x] ? x : (p[x] = get_leader(p[x])));
}

bool merge(int x, int y)
{
	x = get_leader(x);
	y = get_leader(y);
	if(x == y) return false;
	p[x] = y;
	return true;
}

int main()
{
	int n, m;
	scanf("%d %d", &n, &m);
	for(int i = 0; i < n; i++)
		scanf("%lld", &a[i]);
	vector<edge> es(m);
	for(int i = 0; i < m; i++)
	{
		scanf("%d %d %lld", &es[i].y.x, &es[i].y.y, &es[i].x);
		es[i].y.x--;
		es[i].y.y--;
	}
	int z = min_element(a, a + n) - a;
	for(int i = 0; i < n; i++)
		if(i != z)
			es.push_back(mp(a[i] + a[z], mp(i, z)));
	sort(es.begin(), es.end());
	long long ans = 0;
	for(int i = 0; i < n; i++)
		p[i] = i;
	for(auto e : es)
		if(merge(e.y.x, e.y.y))
			ans += e.x;
	printf("%lld\n", ans);
	return 0;		
}