#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

int op(int x, int y) { return min(x, y); }
int e() { return 1001001001; }


template<class T, class Compare=less<T>>
pair<vector<array<int, 2>>, int> cartesian_tree(const vector<T>& a) {
  const int n = a.size();
  vector<array<int, 2>> g(n, {-1, -1});
  vector<int> st;
  constexpr Compare cmp;
  for (int i = 0; i < n; i++) {
    int last_popped = -1;
    while (!st.empty() && cmp(a[i], a[st.back()])) {
      last_popped = st.back(); st.pop_back();
    }
    g[i][0] = last_popped;
    if (!st.empty()) g[st.back()][1] = i;
    st.emplace_back(i);
  }
  return pair(move(g), st.empty() ? -1 : st[0]);
}


} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, q;
  cin >> n >> q;
  string s;
  cin >> s;
  VI sa = suffix_array(s);
  VI lcp = lcp_array(s, sa);
  segtree<int, op, e> seg(lcp);
  VI sa_inv(n);
  rep(i, n) sa_inv[sa[i]] = i;
  VL acc(n + 1);
  rep(i, n) acc[i + 1] = acc[i] + n - sa[i];
  VL d(n + 1);
  {
    auto [to, root] = cartesian_tree(lcp);
    auto dfs = [&](auto&& self, int u, int l, int r) {
      if (u == -1) {
        assert(r - l == 1);
        if (l) {
          d[l] += lcp[l-1];
          d[r] -= lcp[l-1];
        }
        return;
      }
      assert(u != -1);
      ll v = ll(r - (u + 1)) * lcp[u];
      d[0] += v;
      d[u + 1] -= v;
      self(self, to[u][0], l, u + 1);
      self(self, to[u][1], u + 1, r);
    };
    dfs(dfs, root, 0, n);
    rep(i, n) d[i+1] += d[i];
  }
  rep(_, q) {
    int l, r;
    cin >> l >> r;
    l--;
    int len = r - l;
    int i = sa_inv[l];
    int li = seg.min_left(i, [&](int x) {
      return x >= len;
    });
    int ri = seg.max_right(i, [&](int x) {
      return x >= len;
    });
    ll ans = ll(ri - li + 1) * (len - 1);
    ans += acc[li];
    ans += d[ri+1];
    cout << ans << '\n';
  }
}