n,Q=map(int,input().split())
s=input()
K=26
c=[[0]*(n+1) for i in range(K)]
for i in range(n):
  c[ord(s[i])-ord("a")][i]+=1
  for j in range(K):
    c[j][i]+=c[j][i-1]
for _ in range(Q):
  l,r,x=map(int,input().split())
  l-=1
  r-=1
  g=0
  for i in range(K):
    d=c[i][r]-c[i][l-1]
    if x<=g+d:
      print(chr(i+ord("a")))
      break
    g+=d