n,Q = map(int,input().split())
s = input()
r = [[0]*(n+1) for _ in range(26)]
for i in range(n)[::-1]:
    for j in range(26):
        r[j][i] = r[j][i+1]
    v = ord(s[i])- 97
    r[v][i] += 1

for _ in range(Q):
    L,R,x = map(int,input().split())
    v = 0
    for i in range(26):
        v += r[i][L-1] - r[i][R]
        if v >= x: break
    print(chr(97+i))