using System;

public class Hello
{
    public static string AL = "abcdefghijklmnopqrstuvwxyz";
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = int.Parse(line[0]);
        var q = int.Parse(line[1]);
        var s = Console.ReadLine().Trim();
        var aa = new int[26, n + 1];
        for (int i = 0; i < 26; i++)
        {
            for (int j = 0; j < n; j++)
                aa[i, j + 1] = s[j] == AL[i] ? aa[i, j] + 1 : aa[i, j];
        }
        getAns(aa, q);
    }
    static void getAns(int[,] aa, int q)
    {
        for (int i = 0; i < q; i++)
        {
            string[] line = Console.ReadLine().Trim().Split(' ');
            var L = int.Parse(line[0]);
            var r = int.Parse(line[1]);
            var x = int.Parse(line[2]);
            var count = 0;
            for (int j = 0; j < 26; j++)
            {
                count += aa[j, r] - aa[j, L - 1];
                if (count >= x) { Console.WriteLine(AL[j]); break; }
            }
        }
    }
}