N,Q = map(int,input().split())
S = input()
lsalpha = 'abcdefghijklmnopqrstuvwxyz'
d = dict()
for i in range(26):
    d[lsalpha[i]] = i
ll = []
for i in range(N):
    ll.append(d[S[i]])
lsQ = []
for i in range(Q):
    l,r,x = map(int,input().split())
    l -= 1
    lsQ.append((l,r,x))

la = [[0]*(N+1) for i in range(26)]
for i in range(26):
    for j in range(N):
        la[i][j+1] = la[i][j]+(i==ll[j])

for i in range(Q):
    l,r,x = lsQ[i]
    c = 0
    v = 0
    for j in range(26):
        c += la[j][r]-la[j][l]
        if c >= x:
            v = j
            break
    print(lsalpha[v])