#include <bits/stdc++.h>

using namespace std;

int main() {
   ios::sync_with_stdio(false);
   cin.tie(0);
   int n, q;
   string s;
   cin >> n >> q >> s;
   vector<vector<int>> c(26, vector<int>(n + 1, 0));
   for (int i = 0; i < n; i++) {
       c[s[i] - 'a'][i + 1]++;
   }
   for (int i = 0; i < 26; i++) {
       for (int j = 0; j < n; j++) {
           c[i][j + 1] += c[i][j];
       }
   }
   while(q--) {
       int l, r, x;
       cin >> l >> r >> x;
       int a = 0;
       int ans = 0;
       for (int i = 0; i < 26; i++) {
           a += c[i][r] - c[i][l - 1];
           if (a >= x) {
               ans = i;
               break;
           }
       }
       cout << (char) ('a' + ans) << endl;
   }
}