N,Q = map(int,input().split())
S = "0"+input().strip()
C = {chr(i):[0 for _ in range(N+1)] for i in range(97,123)}
for i in range(1,N+1):
    for j in range(97,123):
        C[chr(j)][i] = C[chr(j)][i-1]
    C[S[i]][i] += 1
for _ in range(Q):
    l,r,x = map(int,input().split())
    cnt = 0
    for j in range(97,123):
        n = C[chr(j)][r]-C[chr(j)][l-1]
        if cnt+n>=x:
            print(chr(j))
            break
        cnt += n