#include <iostream>
#include <vector>
#include <string>

int main()
{
    int n, queries;
    std::string s;

    std::cin >> n >> queries >> s;

    std::vector<std::vector<int>> counts(n + 1, std::vector<int>(26));

    for (size_t i = 0; i < s.length(); i++)
    {
        auto c = s[i] - 'a';
        counts[i + 1][c]++;

        for (size_t j = 0; j < 26; j++)
        {
            counts[i + 1][j] += counts[i][j];
        }
    }

    for (size_t q = 0; q < queries; q++)
    {
        int l, r, k;
        std::cin >> l >> r >> k;
        l--;

        int sum = 0;

        for (size_t i = 0; i < 26; i++)
        {
            sum += counts[r][i] - counts[l][i];

            if (sum >= k)
            {
                std::cout << (char)(i + 'a') << std::endl;
                break;
            }
        }
    }
}