import sys
input = sys.stdin.readline

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

X=[[0]*26 for i in range(len(S)+1)]
for i in range(len(S)):
    x=ord(S[i])-97
    for j in range(26):
        X[i][j]=X[i-1][j]
        
    X[i][x]+=1

#print(X)

for q in range(Q):
    l,r,x=map(int,input().split())
    l-=1
    r-=1
    Y=[0]*26
    for j in range(26):
        Y[j]+=X[r][j]
        Y[j]-=X[l-1][j]

    now=0
    for j in range(26):
        now+=Y[j]
        if now>=x:
            print(chr(97+j))
            break