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], temp[2])
        })
        .collect::<Vec<_>>();

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