N, Q = map(int, input().split())
S = input()
C = [[0] * (26) for i in range(N + 1)]
for i in range(N):
    for j in range(26):
        if j == ord(S[i]) - ord("a"):
            C[i + 1][j] = C[i][j] + 1
        else:
            C[i + 1][j] = C[i][j]

for q in range(Q):
    L, R, X = map(int, input().split())
    L -= 1
    n = 0
    for j in range(26):
        n += C[R][j] - C[L][j]
        if n >= X:
            print(chr(ord("a") + j))
            break