import sys,math,itertools
from collections import Counter,deque,defaultdict
from bisect import bisect_left,bisect_right 
from heapq import heappop,heappush,heapify
mod = 10**9+7
INF = float('inf')
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_1(): return list(map(lambda x:int(x)-1, sys.stdin.readline().split()))
def inps(): return sys.stdin.readline()
def inpsl(x): tmp = inps(); return list(tmp[:x])
def err(x): print(x); exit()

n,q = inpl()
s = input()
ac = [[0]*26 for _ in range(n+1)]
for i,x in enumerate(s):
    for j in range(26):
        tmp = 1 if 97+j == ord(x) else 0
        ac[i+1][j] = ac[i][j] + tmp

for _ in range(q):
    l,r,X = inpl()
    cnt = 0
    for j in range(26):
        cnt += ac[r][j] - ac[l-1][j]
        if cnt >= X:
            print(chr(97+j))
            break