#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define vb vector<bool>
#define ed "\n"
#define fi first
#define se second
#define pll pair<ll, ll>
#define ff(aa, bb, cc) for(ll aa = bb; aa < cc; aa++)
#define pb push_back
#define all(aaa) aaa.begin(), aaa.end()
int main(){
ll n, m;
cin >> n >> m;
map<ll, set<ll>> conexiones;
ll c = 0;
ff(i, 0, m){
ll a, b;
cin >> a >> b;
a--;
b--;
conexiones[a].insert(b);
}
ff(i, 0, n){
if(conexiones[i].empty()){
continue;
}
auto val = *conexiones[i].begin();
/*cout << i+1 << " " << conexiones[i].size() << ed;
for(auto p : conexiones[i]){
cout << " " << p+1;
}
cout << ed*/
c += conexiones[i].size();
conexiones[i].erase(val);
//cout << "V " << val+1 << ed;
if(conexiones[i].size()>conexiones[val].size()){
//cout << "SWAP " << i+1 << " " << val+1 << ed;
swap(conexiones[i], conexiones[val]);
}
// cout << "ACT";
for(auto p : conexiones[i]){
//cout << " " << p+1;
conexiones[val].insert(p);
}
//cout << ed << ed;
}
cout << c << ed;
return 0;
}
