from collections import defaultdict
n,m = map(int,input().split())
s = list(map(str,input()))
ss = sorted(s)
d = defaultdict(list)
for i in range(26):
    d[chr(97+i)].append(0)
    for j in range(n):
        if(s[j] == chr(97+i)):
            d[chr(97+i)].append(d[chr(97+i)][-1] + 1)
        else:
            d[chr(97+i)].append(d[chr(97+i)][-1])

for _ in range(m):
    a,b,c = map(int,input().split())
    cnt = 0
    for key in d:
        cnt += d[key][b] - d[key][a-1]
        if(cnt >= c):
            print(key)
            break