#pragma GCC optimize ("O2")
#pragma GCC target ("avx2")
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define Would
#define you
#define please

int N, M;
const int NV = 400001;
int KL[400001];
vector<int> E[NV], E2[NV];
vector<int> ba, E3[NV];
set<int> vis;
map<int, int> S;
int kazu[NV], memo[NV];
int NS;

int zaatu(int A) {
	return lower_bound(KL, KL + M + M, A) - KL;
}

void dfs1(int a) {
	int A = zaatu(a);
	if (vis.find(A) == vis.end()) {
		vis.insert(A);
		for (int i : E[A]) dfs1(KL[i]);
		ba.pb(a);
	}
}
void dfs2(int a) {
	int A = zaatu(a);
	if (!S[A]) {
		S[A] = NS;
		chmax(kazu[NS], a);
		for (int i : E2[A]) dfs2(KL[i]);
	}
}
int dfs3(int A) {
	if (memo[A]) return memo[A];
	int ret = kazu[A];
	for (int i : E3[A]) chmax(ret, dfs3(i));
	return memo[A] = ret;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> N >> M;

	set<int> list;
	int kl = 0;
	int U[200000], V[200000];
	rep(i, M) {
		int u, v;
		cin >> u >> v;
		U[i] = u;
		V[i] = v;
		KL[kl++] = u;
		KL[kl++] = v;
		list.insert(u);
		list.insert(v);
	}
	sort(KL, KL + M + M);
	rep(i, M) {
		int u = zaatu(U[i]);
		int v = zaatu(V[i]);
		E[u].pb(v);
		E2[v].pb(u);
	}


	for(auto i : list) {
		dfs1(i);
	}
	int m = ba.size();
	for (int i = m - 1; i >= 0; i--) if (S[zaatu(ba[i])] == 0) {
		NS++;
		dfs2(ba[i]);
	}

	for (auto P : list) {
		int p = zaatu(P);
		for (int j : E[p]) {
			if (S[p] != S[j]) E3[S[p]].pb(S[j]);
		}
	}

	//rep1(i, N) {
	//	cesp(i);
	//	int j = zaatu(i);
	//	cesp(j);
	//	ce(S[j]);
	//	for (auto k : E3[S[j]]) {
	//		cesp(k);
	//	}ce("");
	//}

	ll kotae = 0;
	for (auto i : list) {
		kotae -= i;
		int tmp = zaatu(i);
		int j = S[tmp];
		kotae += dfs3(j);
	}
	kotae += ll(N) * (N + 1) / 2;

	co(kotae);

	Would you please return 0;
}