#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <random>
#include <unordered_map>
#include <unordered_set>
#define all(a) a.begin(),a.end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define pb push_back
#define debug(x) cerr << __LINE__ << ' ' << #x << ':' << x << '\n'
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;
typedef complex<ld> com;
constexpr int inf = 1000000010;
constexpr ll INF = 1000000000000000010;
constexpr ld eps = 1e-12;
constexpr ld pi = 3.141592653589793238;
template<class T, class U> inline bool chmax(T &a, const U &b) { if (a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if (a > b) { a = b; return true; } return false; }


int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(20);

	ll n, m;
	cin >> n >> m;
	map<int, vector<int>> graph;
	set<int> st;
	rep(i, m) {
		int b, c;
		cin >> b >> c;
		graph[c].pb(b);
		st.insert(c);
	}
	map<int, int> val;
	while (st.size() > 0) {
		int s = *st.rbegin();
		queue<int> que;
		que.push(s);
		val[s] = s;
		st.erase(s);
		while (!que.empty()) {
			int p = que.front(); que.pop();
			for (int i : graph[p]) {
				if (val.count(i) == 0) {
					val[i] = s;
					que.push(i);
					st.erase(i);
				}
			}
		}
	}
	ll ans = n * (n + 1) / 2;
	for (auto i : val) {
		ll x = i.first;
		ll y = i.second;
		if (x < y) ans += y - x;
	}
	cout << ans << '\n';
}