n, q = map(int,input().split())
S = input()

alp = [[0]*26 for _ in range(n+1)]
for i,s in enumerate(S):
    i += 1
    for j in range(26):
        alp[i][j] = alp[i-1][j]
    alp[i][ord(s)-ord("a")] += 1
    

for j in range(q):
    l, r, x = map(int,input().split())
    now = 0
    for i in range(26):
        now += alp[r][i]-alp[l-1][i]
        if now >= x:
            print(chr(i+ord("a")))
            break