#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

map<int, int> zip;
vector<int> unzip;
template <typename T> void compress(vector<T>& v) {
  for (int i = 0; i < (int) v.size(); i++) unzip.push_back(v[i]);
  sort(unzip.begin(), unzip.end());
  unzip.erase(unique(unzip.begin(), unzip.end()), unzip.end());
  for (int i = 0; i < (int) unzip.size(); i++) zip[unzip[i]] = i;
}

class StronglyConnectedComponents {
private:
  int siz;
  int itr = 0;
  vector<bool> done;
  vector<int> order, comp;
  void dfs (int cur, const vector<vector<int>>& g) {
    done[cur] = true;
    for (int nxt : g[cur]) {
      if (!done[nxt]) dfs(nxt, g);
    }
    order.push_back(cur);
  }
  void rdfs (int cur, const vector<vector<int>>& rg) {
    done[cur] = true;
    comp[cur] = itr;
    for (int nxt : rg[cur]) {
      if (!done[nxt]) rdfs(nxt, rg);
    }
  }
  void build (const vector<vector<int>>& g, const vector<vector<int>>& rg) {
    for (int i = 0; i < siz; ++i) if (!done[i]) dfs (i, g);
    reverse(order.begin(), order.end());
    fill(done.begin(), done.end(), false);
    for (int i = 0; i < siz; ++i) if (!done[order[i]]) rdfs (order[i], rg), ++itr;
  }

public:
  StronglyConnectedComponents(const vector<vector<int>>& g, const vector<vector<int>>& rg, const int& n) : siz(n), done(siz, false), comp(siz, -1) {
    build(g, rg);
  }
  bool  has_cycle() { return *max_element(comp.begin(), comp.end()) < siz - 1; }
  vector<int> get_comp() { return comp;}
};
using SCC = StronglyConnectedComponents;

map<int, int> memo;
int dfs (int cur, vector<set<int>>& g, vector<int>& val) {
  if (memo.count(cur)) return memo[cur];
  assert(cur < (int) val.size());
  memo[cur] = val[cur];
  for (int nxt : g[cur]) {
    memo[cur] = max(memo[cur], dfs(nxt, g, val));
  }
  return memo[cur];
}

signed main() { 
  ios::sync_with_stdio(false); cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<int> all;
  vector<int> b(m), c(m);
  for (int i = 0; i < m; i++) {
    cin >> b[i] >> c[i];
    all.push_back(b[i]);
    all.push_back(c[i]);
  }
  compress(all);
  vector<int> bb(m), cc(m);
  int nn = zip.size();
  vector<vector<int>> g(nn), rg(nn);
  for (int i = 0; i < m; i++) {
    g[zip[b[i]]].push_back(zip[c[i]]);
    rg[zip[c[i]]].push_back(zip[b[i]]);
  }
  SCC scc(g, rg, nn);
  auto comp = scc.get_comp();
  int nnn = *max_element(comp.begin(), comp.end()) + 1;
  vector<int> comp_v(nnn);
  for (int i = 0; i < m; i++) {
    comp_v[comp[zip[c[i]]]] = max(comp_v[comp[zip[c[i]]]], c[i]);
    comp_v[comp[zip[b[i]]]] = max(comp_v[comp[zip[c[i]]]], b[i]);
  }
  vector<set<int>> gg(nnn);
  for (int i = 0; i < m; i++) {
    if (comp[zip[b[i]]] == comp[zip[c[i]]]) continue;
    gg[comp[zip[b[i]]]].insert(comp[zip[c[i]]]);
  }
  vector<int> comp_res(nnn);
  for (int i = 0; i < nnn; i++) {
    comp_res[i] = dfs(i, gg, comp_v);
  }
  long long ans = 1LL * n * (n + 1) / 2;
  for (auto& x : unzip) {
    ans += comp_res[comp[zip[x]]] - x;
  }
  cout << ans << endl;
  return 0;
}