#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001

int op(int a,int b){
	return min(a,b);
}

int e(){
	return Inf32;
}
int X;
bool f(int x){
	return x>=X;
}

int main(){
	
	int N,Q;
	cin>>N>>Q;
	
	string S;
	cin>>S;
	
	auto sa = suffix_array(S);
	auto la = lcp_array(S,sa);
	vector<int> pos(N);
	rep(i,sa.size())pos[sa[i]] = i;
	vector<long long> sum(N);
	rep(i,sa.size()){
		sum[i] = N - sa[i];
		if(i!=0)sum[i] += sum[i-1];
	}
	segtree<int,op,e> seg(la);
	rep(_,Q){
		int l,r;
		cin>>l>>r;
		l--;
		
		int p = pos[l];
		
		X = r-l;
		
		int ll = seg.min_left<f>(p);
		int rr = seg.max_right<f>(ll);
		rr++;
		//cout<<ll<<','<<rr<<endl;
		long long ans = rr-ll;
		ans *= X-1;
		if(ll!=0)ans += sum[ll-1];
		cout<<ans<<endl;
	}
	
	return 0;
}