//Let's join Kaede Takagaki Fan Club !!
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(int i=0;i<x;i++)
#define repn(i,x) for(int i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())
#define all(x) x.begin(),x.end()
template<class T>
void dmp(T a){
	rep(i,a.size()) cout << a[i] << " ";
	cout << endl;
}
template<class T>
bool chmax(T&a, T b){
	if(a < b){
		a = b;
		return 1;
	}
	return 0;
}
template<class T>
bool chmin(T&a, T b){
	if(a > b){
		a = b;
		return 1;
	}
	return 0;
}
template<class T>
void g(T &a){
	cin >> a;
}
template<class T>
void o(const T &a,bool space=false){
	cout << a << (space?' ':'\n');
}
//ios::sync_with_stdio(false);
const ll mod = 998244353;
template<class T>
void add(T&a,T b){
	a+=b;
	if(a >= mod) a-=mod;
}

map<int, int>M;
int n, m;
map<int, vector<int>>E;
vector<int>vec;
int main(){
	cin >> n >> m;
	rep(i, m){
		int a, b; cin >> a >> b;
		vec.pb(a); vec.pb(b);
		E[b].pb(a);
	}
	SORT(vec); ERASE(vec);
	reverse(all(vec));
	rep(i, vec.size()){
		int q = vec[i];
		queue<int>que; que.push(q);
		while(!que.empty()){
			int q = que.front(); que.pop();
			if(M.find(q) != M.end()) continue;
			M[q] = vec[i];
			for(auto at:E[q]){
				if(M.find(at) == M.end()) que.push(at);
			}
		}
	}
	ll ans = 1LL*n*(n+1)/2;
	rep(i, vec.size()) ans += M[vec[i]] - vec[i];
	cout << ans << endl;
}