#include<bits/stdc++.h>
using namespace std;
//#include <atcoder/scc>
//using namespace atcoder;
//using mint = modint998244353;
//using mint = modint1000000007;
#pragma region template
using ll = long long;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;
template <class T> using V = vector<T>;
template <class T> using VV = V<V<T>>;
#define overload4(_1,_2,_3,_4,name,...) name
#define overload3(_1,_2,_3,name,...) name
#define rep1(n) for(ll i=0;i<n;++i)
#define rep2(i,n) for(ll i=0;i<n;++i)
#define rep3(i,a,b) for(ll i=a;i<b;++i)
#define rep4(i,a,b,c) for(ll i=a;i<b;i+=c)
#define rep(...) overload4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i=n;i--;)
#define rrep2(i,n) for(ll i=n;i--;)
#define rrep3(i,a,b) for(ll i=b;i-->(a);)
#define rrep(...) overload3(__VA_ARGS__,rrep3,rrep2,rrep1)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define debug(var)  do{std::cerr << #var << " : ";view(var);}while(0)
template<typename T> void view(T e){std::cerr << e << std::endl;}
template<typename T> void view(const std::vector<T>& v){for(const auto& e : v){ std::cerr << e << " "; } std::cerr << std::endl;}
template<typename T> void view(const std::vector<std::vector<T> >& vv){cerr << endl;int cnt = 0;for(const auto& v : vv){cerr << cnt << "th : "; view(v); cnt++;} cerr << endl;}
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
  std::ostream::sentry s(dest);
  if (s) {
    __uint128_t tmp = value < 0 ? -value : value;
    char buffer[128];
    char *d = std::end(buffer);
    do {
      --d;
      *d = "0123456789"[tmp % 10];
      tmp /= 10;
    } while (tmp != 0);
    if (value < 0) {
      --d;
      *d = '-';
    }
    int len = std::end(buffer) - d;
    if (dest.rdbuf()->sputn(d, len) != len) {
      dest.setstate(std::ios_base::badbit);
    }
  }
  return dest;
}
template<class T, class K>bool chmax(T &a, const K b) { if (a<b) { a=b; return 1; } return 0; }
template<class T, class K>bool chmin(T &a, const K b) { if (b<a) { a=b; return 1; } return 0; }
const int inf = 1001001001;
const ll INF = 1001001001001001001ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
ll rddiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // -20 / 3 == -7
ll power(ll a, ll p){ll ret = 1; while(p){if(p & 1){ret = ret * a;} a = a * a; p >>= 1;} return ret;}
ll modpow(ll a, ll p, ll mod){ll ret = 1; while(p){if(p & 1){ret = ret * a % mod;} a = a * a % mod; p >>= 1;} return ret;}
ll rudiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } //  20 / 3 == 7
#pragma endregion
// const double pi = acos(-1);
//const ll mod = 998244353;
const ll mod = 1000000007;


int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    //cout << fixed << setprecision(20);
    int n, m; cin >> n >> m;
    int ans = 0;
    VV<int> G(n);
    rep(i,m){
        int a, b; cin >> a >> b;
        --a, --b;
        G[a].pb(b);
    }
    rep(i,n){
        queue<int> que;
        V<bool> seen(n);
        que.push(i);
        while(que.size()){
            int v = que.front(); que.pop();
            if(seen[v]) continue;
            seen[v] = true;
            ans++;
            for(int nv : G[v]){
                if(!seen[nv]) que.push(nv);
            }
        }
    }
    cout << ans << endl;
}
#include<iostream>
using namespace std;
#include<bits/stdc++.h>
typedef long long int ll;
void dfs(int i,vector<vector<int>>&adj,int vis[]){
  vis[i]=1;
  for(int child:adj[i]){
    if(vis[child]==0)
      dfs(child,adj,vis);
  }
}
int main(){
  int n,m;
  cin>>n>>m;
  vector<vector<int>>adj(n+1);
  int u,v;
  for(int i=1;i<=m;i++){
    cin>>u>>v;
    adj[u].push_back(v);
  }
  ll cnt=0;
  for(int i=1;i<=n;i++){
    int vis[n+1];
    for(int j=1;j<=n;j++)
      vis[j]=0;
    dfs(i,adj,vis);
    for(int j=1;j<=n;j++){
      if(vis[j]==1)
        cnt++;
    }
  }
  cout<<cnt<<endl;
}