n, Q = map(int, input().split())
S = input()
cnt = [[0] * 26 for _ in range(n + 1)]
for i, s in enumerate(S, 1):
    cnt[i] = cnt[i - 1].copy()
    cnt[i][ord(s) - 97] += 1
    
for _ in range(Q):
    l, r, x = map(int, input().split())
    tot = 0
    for i in range(26):
        tot += cnt[r][i] - cnt[l - 1][i]
        if tot >= x:
            print(chr(i + 97))
            break