from bisect import bisect_left
N,Q=map(int,input().split())
S=input()
nums=[[0]*26]
for s in S:
    res=[nums[-1][i] for i in range(26)]
    res[ord(s)-ord("a")]+=1
    nums.append(res)
for _ in range(Q):
    l,r,x=map(int,input().split())
    substring=[0]*26
    for i in range(26):
        substring[i]=nums[r][i]-nums[l-1][i]
    for i in range(25):
        substring[i+1]+=substring[i]
    print(chr(bisect_left(substring,x)+ord("a")))