#include<bits/stdc++.h>
using namespace std;

using ll = long long;
#define fi first
#define se second

int main(){
  int n,q;
  string s;
  cin>>n>>q>>s;
  int count[n+1][26]={};
  for(int i=0;i<n;i++){
    for(int j=0;j<26;j++){
      count[i+1][j]=count[i][j];
    }
    count[i+1][s[i]-'a']++;
  }
  while(q--){
    int l,r,x;
    cin>>l>>r>>x;
    int p=0;
    for(int i=0;i<26;i++){
      if(p+count[r][i]-count[l-1][i]>=x){
        cout<<(char)('a'+i)<<endl;
        break;
      }
      p+=count[r][i]-count[l-1][i];
    }
  }
}