#include <bits/stdc++.h>
#define dbg(x) cerr << #x << ": " << x << '\n';
#define dbgv(v) cerr << #v << ": "; for(auto &el : v) cerr << el << " "; cerr << '\n';
using namespace std;
using ll = long long;
bool test_cases = 0;
void solve(){
ll n, m, ans = 0;
cin >> n >> m;
vector<set<ll>> arr;
arr.assign(n, set<ll>());
for(int i = 0; i < m; i++){
int a, b;
cin >> a >> b;
a--, b--;
arr[a].insert(b);
}
for(int i = 0; i < n; i++){
ans += arr[i].size();
if(arr[i].empty()) continue;
int x = *arr[i].begin();
arr[i].erase(*arr[i].begin());
if(arr[i].size() > arr[x].size()){
swap(arr[i], arr[x]);
}
for(auto &j : arr[i]){
arr[x].insert(j);
}
}
cout << ans;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
if(test_cases){
int t;
cin >> t;
for(int i = 0; i < t; i++){
solve();
}
return 0;
}
solve();
return 0;
}
