n,q=map(int,input().split())
s=input()
ANS=[]
for _ in range(q):
  l,r=map(lambda x:int(x)-1,input().split())
  ans=0
  for i in range(n):
    for j in range(i,n):
      if s[i:j+1]<s[l:r+1]:
        ans+=1
  print(ans)