import collections
N,Q=map(int,input().split())
S=input()

cumsum = [None for i in range(len(S)+1)]
cumsum[0] = [0]*26
chidx = [0]*26
for i,s in enumerate(S, 1):
    chidx[ord(s) - ord('a')] += 1
    cumsum[i] = [a for a in chidx]
#print(chidx)

deq = collections.deque()
for q in range(Q):
    l,r,x=map(int,input().split())
    #print("debu", l, r, x)
    diff = [ri-li for ri,li in zip(cumsum[r], cumsum[l-1])]

    tmp = 0
    for i, d in enumerate(diff, ord('a')):
        tmp += d
        if tmp >= x:
            deq.append(chr(i))
            break
print(*deq,sep='\n')