#include <bits/stdc++.h>
template<class T> inline bool chmin(T&a, T b){if(a > b){a = b; return true;}else{return false;}}
template<class T> inline bool chmax(T&a, T b){if(a < b){a = b; return true;}else{return false;}}
#define ll long long
#define double long double
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=1;i<=(n);i++)
#define mod (ll)(1e9+7)
#define inf (ll)(3e18+7)
#define eps (double)(1e-9)
#define pi (double) acos(-1)
#define P pair<int,int>
#define PiP pair<int,pair<int,int>>
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;

int main() {
    int n, q;
    cin >> n >> q;
    string s;
    cin >> s;
    vector<vector<int>> sum(26, vector<int>(n+1, 0));
    for(char c = 'a'; c <= 'z'; c++){
        REP(i, n)sum[c-'a'][i] += sum[c-'a'][i-1] + (s[i-1] == c);   
    }
    rep(_, q){
        int l, r, x;
        cin >> l >> r >> x;
        int cnt = 0;
        for(char c = 'a'; c <= 'z'; c++){
            cnt += sum[c-'a'][r]-sum[c-'a'][l-1];
            if(cnt >= x){
                cout << c << endl;
                break;
            }
        }
    }
}