#include<iostream>
#include<vector>
#include<algorithm>
#include<cassert>
#include<atcoder/string>
#include<atcoder/segtree>
#include<atcoder/lazysegtree>
using namespace std;
int opmin(int a,int b){return min(a,b);}
int emin(){return(int)1e9;}
using dat=pair<long long,int>;
dat opsum(dat a,dat b)
{
	a.first+=b.first;
	a.second+=b.second;
	return a;
}
dat esum(){return make_pair(0LL,0);}
dat mp(int f,dat x)
{
	x.first+=(long long)f*x.second;
	return x;
}
int cmp(int f,int g){return f+g;}
int id(){return 0;}
int N,Q;
string S;
int inv[2<<17];
int L[1<<17],R[1<<17];
long long ans[1<<17];
vector<int>Qid[1<<17];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>N>>Q>>S;
	vector<int>SA=atcoder::suffix_array(S);
	vector<int>LCP=atcoder::lcp_array(S,SA);
	for(int i=0;i<SA.size();i++)inv[SA[i]]=i;
	atcoder::segtree<int,opmin,emin>lcp_seg(LCP);
	vector<dat>len_init(N);
	for(int i=0;i<N;i++)len_init[i]=make_pair(N-SA[i],1);
	atcoder::lazy_segtree<dat,opsum,esum,int,mp,cmp,id>len_seg(len_init);
	for(int i=0;i<Q;i++)
	{
		cin>>L[i]>>R[i];
		L[i]--;
		int idx=inv[L[i]];
		R[i]=R[i]-L[i];//len
		int l=lcp_seg.min_left(idx,[&i](int x){return x>=R[i];});
		L[i]=l;
		Qid[l].push_back(i);
		ans[i]=len_seg.prod(0,l).first;
	}
	vector<dat>init(N,make_pair(0,1));
	atcoder::lazy_segtree<dat,opsum,esum,int,mp,cmp,id>seg(init);
	vector<pair<int,int> >st;
	for(int i=N;i--;)
	{
		if(i+1<N)
		{
			int len=LCP[i];
			int cnt=0;
			while(!st.empty()&&st.back().second>=len)
			{
				int c=st.back().first;
				seg.apply(len,st.back().second,-c);
				cnt+=c;
				st.pop_back();
			}
			if(cnt>0)
			{
				st.push_back(make_pair(cnt,len));
			}
		}
		seg.apply(0,N-SA[i],1);
		st.push_back(make_pair(1,N-SA[i]));
		for(int id:Qid[i])
		{
			ans[id]+=seg.prod(1,R[id]).first;
		}
	}
	for(int i=0;i<Q;i++)cout<<ans[i]<<"\n";
}