#include <bits/stdc++.h>   #pragma GCC optimize( Ofast )   using namespace std;   const double pi = acos(-1.0);   void cp();   long long gcd(long long a, long long b) {     if (b == 0) return a;     return gcd(b, a % b);   }   long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }   long long fact(long long n) {     if (n <= 1) return n;     return n * fact(n - 1);   }   bool prime[100001];   void sieve() {     int n = 10000;     memset(prime, true, sizeof(prime));     for (int p = 2; p * p <= n; p++) {       if (prime[p] == true) {         for (int i = p * p; i <= n; i += p) prime[i] = false;       }     }   }   void solve() {     int n, i;     cin >> n;     string s;     cin >> s;     for (i = 0; i <= (2 * n) - 1; i++) {       if (i % 2 == 0) cout << s[i];     }     cout <<   n ;   }   int main() {     cp();     int t;     cin >> t;     while (t--) solve();     return 0;   }   void cp() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);   }   