#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (int i=a;i<b;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}

namespace atcoder {

namespace internal {

std::vector<int> sa_naive(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> sa(n);
    std::iota(sa.begin(), sa.end(), 0);
    std::sort(sa.begin(), sa.end(), [&](int l, int r) {
        if (l == r) return false;
        while (l < n && r < n) {
            if (s[l] != s[r]) return s[l] < s[r];
            l++;
            r++;
        }
        return l == n;
    });
    return sa;
}

std::vector<int> sa_doubling(const std::vector<int>& s) {
    int n = int(s.size());
    std::vector<int> sa(n), rnk = s, tmp(n);
    std::iota(sa.begin(), sa.end(), 0);
    for (int k = 1; k < n; k *= 2) {
        auto cmp = [&](int x, int y) {
            if (rnk[x] != rnk[y]) return rnk[x] < rnk[y];
            int rx = x + k < n ? rnk[x + k] : -1;
            int ry = y + k < n ? rnk[y + k] : -1;
            return rx < ry;
        };
        std::sort(sa.begin(), sa.end(), cmp);
        tmp[sa[0]] = 0;
        for (int i = 1; i < n; i++) {
            tmp[sa[i]] = tmp[sa[i - 1]] + (cmp(sa[i - 1], sa[i]) ? 1 : 0);
        }
        std::swap(tmp, rnk);
    }
    return sa;
}

// SA-IS, linear-time suffix array construction
// Reference:
// G. Nong, S. Zhang, and W. H. Chan,
// Two Efficient Algorithms for Linear Time Suffix Array Construction
template <int THRESHOLD_NAIVE = 10, int THRESHOLD_DOUBLING = 40>
std::vector<int> sa_is(const std::vector<int>& s, int upper) {
    int n = int(s.size());
    if (n == 0) return {};
    if (n == 1) return {0};
    if (n == 2) {
        if (s[0] < s[1]) {
            return {0, 1};
        } else {
            return {1, 0};
        }
    }
    if (n < THRESHOLD_NAIVE) {
        return sa_naive(s);
    }
    if (n < THRESHOLD_DOUBLING) {
        return sa_doubling(s);
    }

    std::vector<int> sa(n);
    std::vector<bool> ls(n);
    for (int i = n - 2; i >= 0; i--) {
        ls[i] = (s[i] == s[i + 1]) ? ls[i + 1] : (s[i] < s[i + 1]);
    }
    std::vector<int> sum_l(upper + 1), sum_s(upper + 1);
    for (int i = 0; i < n; i++) {
        if (!ls[i]) {
            sum_s[s[i]]++;
        } else {
            sum_l[s[i] + 1]++;
        }
    }
    for (int i = 0; i <= upper; i++) {
        sum_s[i] += sum_l[i];
        if (i < upper) sum_l[i + 1] += sum_s[i];
    }

    auto induce = [&](const std::vector<int>& lms) {
        std::fill(sa.begin(), sa.end(), -1);
        std::vector<int> buf(upper + 1);
        std::copy(sum_s.begin(), sum_s.end(), buf.begin());
        for (auto d : lms) {
            if (d == n) continue;
            sa[buf[s[d]]++] = d;
        }
        std::copy(sum_l.begin(), sum_l.end(), buf.begin());
        sa[buf[s[n - 1]]++] = n - 1;
        for (int i = 0; i < n; i++) {
            int v = sa[i];
            if (v >= 1 && !ls[v - 1]) {
                sa[buf[s[v - 1]]++] = v - 1;
            }
        }
        std::copy(sum_l.begin(), sum_l.end(), buf.begin());
        for (int i = n - 1; i >= 0; i--) {
            int v = sa[i];
            if (v >= 1 && ls[v - 1]) {
                sa[--buf[s[v - 1] + 1]] = v - 1;
            }
        }
    };

    std::vector<int> lms_map(n + 1, -1);
    int m = 0;
    for (int i = 1; i < n; i++) {
        if (!ls[i - 1] && ls[i]) {
            lms_map[i] = m++;
        }
    }
    std::vector<int> lms;
    lms.reserve(m);
    for (int i = 1; i < n; i++) {
        if (!ls[i - 1] && ls[i]) {
            lms.push_back(i);
        }
    }

    induce(lms);

    if (m) {
        std::vector<int> sorted_lms;
        sorted_lms.reserve(m);
        for (int v : sa) {
            if (lms_map[v] != -1) sorted_lms.push_back(v);
        }
        std::vector<int> rec_s(m);
        int rec_upper = 0;
        rec_s[lms_map[sorted_lms[0]]] = 0;
        for (int i = 1; i < m; i++) {
            int l = sorted_lms[i - 1], r = sorted_lms[i];
            int end_l = (lms_map[l] + 1 < m) ? lms[lms_map[l] + 1] : n;
            int end_r = (lms_map[r] + 1 < m) ? lms[lms_map[r] + 1] : n;
            bool same = true;
            if (end_l - l != end_r - r) {
                same = false;
            } else {
                while (l < end_l) {
                    if (s[l] != s[r]) {
                        break;
                    }
                    l++;
                    r++;
                }
                if (l == n || s[l] != s[r]) same = false;
            }
            if (!same) rec_upper++;
            rec_s[lms_map[sorted_lms[i]]] = rec_upper;
        }

        auto rec_sa =
            sa_is<THRESHOLD_NAIVE, THRESHOLD_DOUBLING>(rec_s, rec_upper);

        for (int i = 0; i < m; i++) {
            sorted_lms[i] = lms[rec_sa[i]];
        }
        induce(sorted_lms);
    }
    return sa;
}

}  // namespace internal

std::vector<int> suffix_array(const std::vector<int>& s, int upper) {
    assert(0 <= upper);
    for (int d : s) {
        assert(0 <= d && d <= upper);
    }
    auto sa = internal::sa_is(s, upper);
    return sa;
}

template <class T> std::vector<int> suffix_array(const std::vector<T>& s) {
    int n = int(s.size());
    std::vector<int> idx(n);
    iota(idx.begin(), idx.end(), 0);
    sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; });
    std::vector<int> s2(n);
    int now = 0;
    for (int i = 0; i < n; i++) {
        if (i && s[idx[i - 1]] != s[idx[i]]) now++;
        s2[idx[i]] = now;
    }
    return internal::sa_is(s2, now);
}

std::vector<int> suffix_array(const std::string& s) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return internal::sa_is(s2, 255);
}

// Reference:
// T. Kasai, G. Lee, H. Arimura, S. Arikawa, and K. Park,
// Linear-Time Longest-Common-Prefix Computation in Suffix Arrays and Its
// Applications
template <class T>
std::vector<int> lcp_array(const std::vector<T>& s,
                           const std::vector<int>& sa) {
    int n = int(s.size());
    assert(n >= 1);
    std::vector<int> rnk(n);
    for (int i = 0; i < n; i++) {
        rnk[sa[i]] = i;
    }
    std::vector<int> lcp(n - 1);
    int h = 0;
    for (int i = 0; i < n; i++) {
        if (h > 0) h--;
        if (rnk[i] == 0) continue;
        int j = sa[rnk[i] - 1];
        for (; j + h < n && i + h < n; h++) {
            if (s[j + h] != s[i + h]) break;
        }
        lcp[rnk[i] - 1] = h;
    }
    return lcp;
}

std::vector<int> lcp_array(const std::string& s, const std::vector<int>& sa) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return lcp_array(s2, sa);
}

// Reference:
// D. Gusfield,
// Algorithms on Strings, Trees, and Sequences: Computer Science and
// Computational Biology
template <class T> std::vector<int> z_algorithm(const std::vector<T>& s) {
    int n = int(s.size());
    if (n == 0) return {};
    std::vector<int> z(n);
    z[0] = 0;
    for (int i = 1, j = 0; i < n; i++) {
        int& k = z[i];
        k = (j + z[j] <= i) ? 0 : std::min(j + z[j] - i, z[i - j]);
        while (i + k < n && s[k] == s[i + k]) k++;
        if (j + z[j] < i + z[i]) j = i;
    }
    z[0] = n;
    return z;
}

std::vector<int> z_algorithm(const std::string& s) {
    int n = int(s.size());
    std::vector<int> s2(n);
    for (int i = 0; i < n; i++) {
        s2[i] = s[i];
    }
    return z_algorithm(s2);
}

}  // namespace atcoder

using atcoder::lcp_array;
using atcoder::suffix_array;
using atcoder::z_algorithm;

namespace po167{
template <class T,T (*op)(T,T),T(*e)()>
struct segment_tree{
	int _n,size;
	std::vector<T> seg;
	int ceil_pow2(int a){
		int b=1;
		while(a>b){
			b<<=1;
		}
		return b;
	}
	void update(int k){seg[k]=op(seg[k*2],seg[k*2+1]);};
	segment_tree(int n) :_n(n){
		size=ceil_pow2(n);
		seg=std::vector<T>(size*2,e());
	}
	segment_tree(std::vector<T> &p) :_n((int) p.size()){
		size=ceil_pow2(_n);
		seg=std::vector<T>(size*2,e());
		for(int i=0;i<_n;i++) seg[i+size]=p[i];
		for(int i=size-1;i>0;i--) update(i);
	}
	void set(int ind,T val){
		assert(0<=ind&&ind<_n);
		ind+=size;
		seg[ind]=val;
		while(ind!=1){
			ind>>=1;
			update(ind);
		}
	}
    void addl(int ind,T val){
        set(ind,op(get(ind),val));
    }
    void addr(int ind,T val){
        set(ind,op(val,get(ind)));
    }
	T get(int ind){
		assert(0<=ind&&ind<_n);
		return seg[ind+size];
	}
	T query(int l,int r){
		assert(0<=l&&l<=r&&r<=_n);
		T l_val=e();
		T r_val=e();
		l+=size,r+=size;
		while(l<r){
			if(l&1) l_val=op(l_val,seg[l]),l+=1;
			if(r&1) r-=1,r_val=op(seg[r],r_val);
			r>>=1;
			l>>=1;
		}
		return op(l_val,r_val);
	}
	template <bool (*f)(T)> int max_right(int l) {
        return max_right(l, [](T x) { return f(x); });
    }
	template <class F> int max_right(int l, F f) {
		assert(0<=l&&l<=_n);
		assert(f(e()));
		if(f(query(l,_n))) return _n;
		T val=e();
		l+=size;
		while(true){
			while(l%2==0) l>>=1;
			if(!f(op(val,seg[l]))){
				while(l<size){
					l*=2;
					if(f(op(val,seg[l]))){
						val=op(val,seg[l]);
						l++;
					}
				}
				return l-size;
			}
			val=op(val,seg[l]);
			l++;
		}
	}
	template <bool (*f)(T)> int min_left(int r) {
        return min_left(r, [](T x) { return f(x); });
    }
    template <class F> int min_left(int r, F f) {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        T sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(seg[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(seg[r], sm))) {
                        sm = op(seg[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(seg[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

};
}
using po167::segment_tree;


using F= pair<ll,ll>;
F op(F a,F b){return min(a,b);}
F e(){return {INF,INF};}




void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,0,t) solve();
}

void solve(){
	ll N,Q;
	cin>>N>>Q;
	string S;
	cin>>S;
	vector<ll> L(Q),R(Q);
	rep(i,0,Q){
		cin>>L[i]>>R[i];
		L[i]--;
	}
	auto sa=suffix_array(S);
	auto lcp=lcp_array(S,sa);
	vector<ll> rev(N);
	rep(i,0,N) rev[sa[i]]=i;
	vector<ll> order(Q);
	rep(i,0,Q){
		order[i]=i;
	}
	sort(all(order),[&](int l,int r){
		return rev[L[l]]<rev[L[r]];
	});
	segment_tree<F,op,e> seg1(N-1),seg2(Q);
	rep(i,0,Q) seg2.set(i,{R[order[i]]-L[order[i]],i});
	rep(i,0,N-1) seg1.set(i,{lcp[i],i+1});
	vector<ll> ans(Q);
	ll val=0;
	auto f=[&](auto self,ll l1,ll r1,ll l2,ll r2,ll depth)->void{
		auto med1=seg1.query(l1,r1-1);
		//cout<<l1<<" "<<r1<<" "<<l2<<" "<<r2<<"#"<<endl;
		while(true){
			auto tmp=seg2.query(l2,r2);
			//cout<<tmp.first<<" "<<tmp.second<<endl;
			if(tmp.first==INF) break;
			if(tmp.first>med1.first) break;
			seg2.set(tmp.second,e());
			int a=order[tmp.second];
			ans[a]=val+(r1-l1)*(R[a]-L[a]-1-depth);
		}
		if(l1+1==r1){
			val+=N-sa[l1]-depth;
			return;
		}
		//cout<<l1<<" "<<r1<<" "<<med1.first<<" "<<med1.second<<endl;
		seg1.set(med1.second-1,e());
		int medl=l2-1,medr=r2;
		while(medr-medl>1){
			int med=(medl+medr)/2;
			if(med1.second<=rev[L[order[med]]]) medr=med;
			else medl=med;
		}
		val+=(r1-l1)*(med1.first-depth);
		self(self,l1,med1.second,l2,medr,med1.first);
		self(self,med1.second,r1,medr,r2,med1.first);
	};
	//vec_out(rev);
	f(f,0,N,0,Q,0);
	assert(val==N*(N+1)/2);
	for(auto x:ans) cout<<x<<"\n";
}