#![allow(non_snake_case)]
#![allow(unused_imports)]
//use itertools::Itertools;
//use proconio::input;
//use proconio::marker::*;
use std::cmp::Reverse;
use std::collections::*;

fn main() {
    input! {
        n:usize,
        q:usize,
        s:chars,
        query:[(usize1,usize1,usize);q],
    }

    let s = s.into_iter().map(|si| si as u8 - b'a').collect::<Vec<_>>();
    let mut cnts0 = vec![vec![0; n + 1]; 26];
    let mut cnts1 = vec![vec![0; n + 1]; 26];
    for c in 0..26 {
        for i in 0..n {
            cnts0[c][i + 1] += cnts0[c][i];
            cnts1[c][i + 1] += cnts1[c][i];
            if s[i] <= c as u8 {
                cnts0[c][i + 1] += 1;
            }

            if s[i] == c as u8 {
                cnts1[c][i + 1] += 1;
            }
        }
    }
    for (l, r, x) in query {
        for c in 0..26 {
            let cnt1 = cnts0[c][r + 1] - cnts0[c][l];
            let cnt0 = cnts1[c][r + 1] - cnts1[c][l];

            if cnt0 != 0 && cnt1 - cnt0 < x && x <= cnt1 {
                println!("{}", (c as u8 + b'a') as char);
            }
        }
    }
}
mod input {
    #[macro_export]
    macro_rules! input {
        (source = $s:expr, $($r:tt)*) => {
            let mut iter = $s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
        ($($r:tt)*) => {
            let s = {
                use std::io::Read;
                let mut s = String::new();
                std::io::stdin().read_to_string(&mut s).unwrap();
                s
            };
            let mut iter = s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
    }

    #[macro_export]
    macro_rules! input_inner {
        ($iter:expr) => {};
        ($iter:expr, ) => {};

        ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
            let $var = read_value!($iter, $t);
            input_inner!{$iter $($r)*}
        };
    }

    #[macro_export]
    macro_rules! read_value {
        ($iter:expr, ( $($t:tt),* )) => {
            ( $(read_value!($iter, $t)),* )
        };

        ($iter:expr, [ $t:tt ; $len:expr ]) => {
            (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
        };

        ($iter:expr, chars) => {
            read_value!($iter, String).chars().collect::<Vec<char>>()
        };

        ($iter:expr, usize1) => {
            read_value!($iter, usize) - 1
        };

        ($iter:expr, $t:ty) => {
            $iter.next().unwrap().parse::<$t>().expect("Parse error")
        };
    }
}