n = int(input())
for i in range(n):
x = int(input())
s = input()
k =""
for j in range(0,x):
k = k+s[x-1]
print(k)
//Idk how it works but it works
//¯\_(ツ)_/¯
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
using namespace std;
#define int long long
#define ll long long
#define cy cout << "YES"
#define cn cout << "NO"
#define eb emplace_back
#define itn int
#define fro for
#define cotu cout
void output( bool fl ) {
if( fl ) cy;
else cn;
cout << endl;
}
int solve ( ) {
int n;
cin >> n;
string s;
cin >> s;
for( int i = 0; i < n; i++ ) {
cout << s[n - 1];
}
cout << endl;
}
main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin.exceptions(ios::badbit | ios::failbit);
setlocale( LC_ALL, "Ukr" );
int t = 1;
cin >> t;
while( t-- ) {
solve();
}
return 0;
}
262A - Roma and Lucky Numbers | 1634B - Fortune Telling |
1358A - Park Lighting | 253C - Text Editor |
365B - The Fibonacci Segment | 75A - Life Without Zeros |
1519A - Red and Blue Beans | 466A - Cheap Travel |
659E - New Reform | 1385B - Restore the Permutation by Merger |
706A - Beru-taxi | 686A - Free Ice Cream |
1358D - The Best Vacation | 1620B - Triangles on a Rectangle |
999C - Alphabetic Removals | 1634C - OKEA |
1368C - Even Picture | 1505F - Math |
1473A - Replacing Elements | 959A - Mahmoud and Ehab and the even-odd game |
78B - Easter Eggs | 1455B - Jumps |
1225C - p-binary | 1525D - Armchairs |
1257A - Two Rival Students | 1415A - Prison Break |
1271A - Suits | 259B - Little Elephant and Magic Square |
1389A - LCM Problem | 778A - String Game |