N,Q = map(int,input().split())
S = list(input())

alpha = [0]*26
cumsum = [alpha[:]]
for s in S:
    idx = ord(s)-97
    alpha[idx] += 1
    cumsum.append(alpha[:])

for _ in range(Q):
    l,r,x = map(int,input().split())

    chr_list = [0]*26

    cnt = 0
    for i in range(26):
        chr_list[i] = cumsum[r][i] - cumsum[l-1][i]
        cnt += chr_list[i]
        if cnt >= x:
            print(chr(97+i))
            break