//
// Created by yamunaku on 2020/08/22.
//

#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (n); i++)
#define repl(i, l, r) for(int i = (l); i < (r); i++)
#define per(i, n) for(int i = ((n)-1); i >= 0; i--)
#define perl(i, l, r) for(int i = ((r)-1); i >= (l); i--)
#define all(x) (x).begin(),(x).end()
#define MOD9 998244353
#define MOD1 1000000007
#define IINF 1000000000
#define LINF 1000000000000000000
#define SP <<" "<<
#define CYES cout<<"Yes"<<endl
#define CNO cout<<"No"<<endl
#define CFS cin.tie(0);ios::sync_with_stdio(false)
#define CST(x) cout<<fixed<<setprecision(x)

using ll = long long;
using ld = long double;
using vi = vector<int>;
using mti = vector<vector<int>>;
using vl = vector<ll>;
using mtl = vector<vector<ll>>;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
template<typename T>
using heap = priority_queue<T, vector<T>, function<bool(const T, const T)>>;

map<int, int> name;
mti e;
mti ne;
vi id;
vi col;

void dfs(int x, int &num){
    id[x] = -2;
    for(auto &nx : e[x]){
        if(id[nx] == -1){
            dfs(nx, num);
        }
    }
    id[x] = num++;
}

void dfs2(int x, int c){
    col[x] = c;
    for(auto &nx : ne[x]){
        if(col[nx] == -1){
            dfs2(nx, c);
        }
    }
}

vi ma;
mti ee;
vi visited;

void dfs3(int x){
    visited[x] = true;
    for(auto &nx : ee[x]){
        ma[x] = max(ma[x], ma[nx]);
        if(visited[nx])continue;
        dfs3(nx);
        ma[x] = max(ma[x], ma[nx]);
    }
}

int main(){
    ll n;
    int m;
    scanf("%lld %d", &n, &m);
    vi b(m), c(m);
    rep(i, m){
        scanf("%d %d", &b[i], &c[i]);
        name[b[i]] = name[c[i]] = -1;
    }
    ll ans = n * (n + 1) / 2;
    int tmp = 0;
    for(auto &p : name){
        p.second = tmp++;
        ans -= p.first;
    }
    id = col = vi(tmp, -1);
    e = ne = mti(tmp);
    rep(i, m){
        int u = name[b[i]], v = name[c[i]];
        e[u].push_back(v);
        ne[v].push_back(u);
    }
    int sz = 0;
    rep(i, tmp){
        if(id[i] == -1){
            dfs(i, sz);
        }
    }
    vi a(sz);
    ma = vi(sz, 0);
    rep(i, tmp){
        a[id[i]] = i;
    }
    per(i, sz){
        if(col[a[i]] == -1){
            dfs2(a[i], a[i]);
        }
    }
    for(auto &p : name){
        ma[col[p.second]] = max(ma[col[p.second]], p.first);
    }
    ee = mti(sz);
    rep(i, m){
        ee[col[name[b[i]]]].push_back(col[name[c[i]]]);
    }
    visited = vi(sz);
    rep(i, sz){
        if(visited[i]) continue;
        dfs3(i);
    }
    rep(i, sz){
        ans += ma[col[i]];
    }
    cout << ans << endl;
    return 0;
}