import sys
readline = sys.stdin.readline

def alp_to_num(cha):
    num = ord(cha) - ord("a")
    return num

N, Q = map(int, readline().split())
S = list(input())
S = list(map(alp_to_num, S))
D = [[0] * N for i in range(26)]
Ac = [[0] * (N + 1) for i in range(26)]
for i in range(N):
    D[S[i]][i] = 1
    
for i in range(N):
    for k in range(26):
        Ac[k][i + 1] = Ac[k][i] + D[k][i]
        
for _ in range(Q):
    L, R, X = map(int, readline().split())
    L = L - 1
    cnt = 0
    for k in range(26):
        cnt += Ac[k][R] - Ac[k][L]
        if cnt >= X:
            print(chr(k + ord("a")))
            break