#include<bits/stdc++.h>
using namespace std;
//#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,n) for(int i=1;i<n;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define all(v) v.begin(),v.end()
#define P pair<int,int>
#define len(s) (int)s.size()

template<class T> inline bool chmin(T &a, T b){
	if(a>b){a=b;return true;}
	return false;
}
template<class T> inline bool chmax(T &a, T b){
	if(a<b){a=b;return true;}
	return false;
}
constexpr int mod = 1e9+7;
//constexpr int inf = 3e18;

int N,M;
long long Ans;
int B[200005],C[200005],cnt[400005];
vector<int>xx,G[400005],rG[400005];
bool used[400005];
vector<int>vs;
void dfs(int x){
    used[x]=true;
    for(int i:G[x])if(!used[i])dfs(i);
    vs.push_back(x);
}
int cmp[400005],mx[400005];
vector<int>newrG[400005];
void rdfs(int v,int k){
    used[v]=true;
    cmp[v]=k;
    cnt[k]++;chmax(mx[k],xx[v]);
    for(int i:rG[v])if(!used[i])rdfs(i,k);
}
int scc(){
    rep(i,N)if(!used[i])dfs(i);
    memset(used,0,sizeof(used));
    int k=0;
    rev(i,len(vs))if(!used[vs[i]])rdfs(vs[i],k++);
    rep(i,N){
        for(int j:G[i]){
            newrG[cmp[j]].push_back(cmp[i]);
        }
    }
    return k;
}
signed main(){
    cin.tie(0);ios::sync_with_stdio(false);
    cin>>N>>M;
    rep(i,M){
        cin>>B[i]>>C[i];
        xx.push_back(B[i]);
        xx.push_back(C[i]);
    }
    sort(all(xx));xx.erase(unique(all(xx)),xx.end());
    Ans=(long long)(1+N)*N/2;
    for(int i:xx)Ans-=i;
    rep(i,M){
        B[i]=lower_bound(all(xx),B[i])-xx.begin();
        C[i]=lower_bound(all(xx),C[i])-xx.begin();
        G[B[i]].push_back(C[i]);
        rG[C[i]].push_back(B[i]);
    }
    N=len(xx);
    N=scc();
    rev(i,N){
        Ans+=(long long)mx[i]*cnt[i];
        for(int j:newrG[i])chmax(mx[j],mx[i]);
    }
    cout<<Ans<<endl;
}