#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }


int main() {
  ll N, M; cin >> N >> M;
  ll B[M], C[M]; rep(i,M) cin >> B[i] >> C[i];

  map<ll, ll> m; rep(i,M) { m[B[i]]++; m[C[i]]++; }
  ll nsm = 0; for (auto &x: m) { x.second = nsm; nsm++; };
  rep(i,M) { B[i] = m[B[i]]; C[i] = m[C[i]]; }

  vector<ll> mv; for (auto x: m) mv.push_back(x.first);
  ll S = m.size();
  vector<ll> adj[S]; rep(i,M) adj[C[i]].push_back(B[i]);
  vector<ll> to(S); rep(i,S) to[i] = i;
  per(i,S) {
    if (to[i]==i) {
      queue<ll> q; q.push(i);
      while (q.size()) {
        ll now = q.front(); q.pop();
        for (auto x: adj[now]) {
          if (to[x]<i) {
            to[x] = i;
            q.push(x);
          }
        }
      }
    }
  }  
  // debug(all(to));
  ll result = N*(N+1)/2; rep(i,S) result += mv[to[i]] - mv[i];
  cout << result << endl;
  return 0;
}