const SIZE: usize = 26;

fn main() {
    let mut nq = String::new();
    std::io::stdin().read_line(&mut nq).ok();
    let nq: Vec<usize> = nq.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nq[0];
    let q = nq[1];
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().chars().map(|c| c as usize - 'a' as usize).collect::<Vec<_>>();
    let queries = (0..q).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
            (temp[0]-1, temp[1]-1, temp[2])
        })
        .collect::<Vec<_>>();

    let mut summary = vec![vec![0usize; SIZE]; n+1];
    for i in 0..n {
        for j in 0..SIZE {
            summary[i+1][j] = summary[i][j] + if j == s[i] { 1 } else { 0 };
        }
    }
    let alphabets = "abcdefghijklmnopqrstuvwxyz".chars().collect::<Vec<_>>();
    for &(l, r, x) in queries.iter() {
        let diffs = (0..SIZE).map(|i| summary[r+1][i] - summary[l][i]).collect::<Vec<_>>();
        let mut cnt = 0usize;
        for i in 0..SIZE {
            cnt += diffs[i];
            if cnt >= x {
                println!("{}", alphabets[i]);
                break;
            }
        }
    }
}