#include <bits/stdc++.h>   using namespace std;   const int N = 1e8 + 5;   long long MAX = 1e9;   long long MOD = 1e9 + 7;   long long Mod = 1e9 + 7;   double EPS = 0.0001;   long long gcd(long long a, long long b) { return (b == 0 ? a : gcd(b, a % b)); }   long long lcm(long long a, long long b) { return ((a * b) / gcd(a, b)); }   const int dx[] = {1, -1, 0, 0, 0, 0};   const int dy[] = {0, 0, 1, -1, 0, 0};   int main() {     int n;     string s1;     cin >> n;     cin >> s1;     if (n == 1 || n == 2) {       cout << s1 << endl;       return 0;     }     vector<char> ans(n,  _ );     ans[(n - 1) / 2] = s1[0];     int indx1 = n % 2 == 0 ? n / 2 : n / 2 - 1;     int indx2 = n % 2 == 0 ? n / 2 - 2 : n / 2 + 1;     int dir1 = n % 2 == 0 ? 1 : -1;     int dir2 = n % 2 == 0 ? -1 : 1;     for (int i = 1; i <= n; i++) {       if (i % 2 != 0 && indx1 >= 0 && indx1 < n) {         ans[indx1] = s1[i];         indx1 += dir1;       }       if (i % 2 == 0 && indx2 >= 0 && indx2 < n) {         ans[indx2] = s1[i];         indx2 += dir2;       }     }     for (auto c : ans) cout << c;     cout << endl;     return 0;   }   