mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    N, Q = map(int, input().split())
    S = input().rstrip('\n')
    A = [ord(s) - 97 for s in S]
    cs = [[0] * (N+1) for _ in range(26)]
    for i, a in enumerate(A):
        for j in range(26):
            if a == j:
                cs[j][i+1] = cs[j][i] + 1
            else:
                cs[j][i+1] = cs[j][i]
    for _ in range(Q):
        l, r, x = map(int, input().split())
        cnt = 0
        for j in range(26):
            cnt += cs[j][r] - cs[j][l-1]
            if cnt >= x:
                print(chr(j + 97))
                break


if __name__ == '__main__':
    main()