N,Q = map(int,input().split())
S = str(input())
SA = []
for i in range(26):
    s_temp = [0]
    moji = chr(i+97)
    for j in range(N):
        if S[j] == moji:
            temp = s_temp[-1] + 1
        else:
            temp = s_temp[-1]
        s_temp.append(temp)
    SA.append(s_temp)
#print(SA)

for i in range(Q):
    l,r,x = map(int,input().split())
    l-=1;r-=1
    cnt = 0
    for j in range(26):
        temp = SA[j][r+1] - SA[j][l]
        cnt += temp
        if cnt >= x:
            ans = chr(j+97)
            break
    print(ans)