#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll=long long;
#define rep(i,n) for(int i=0;i<(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

struct UnionFind {
    vector<int> par, siz;
    UnionFind(int n) : par(n,-1), siz(n,1) {}
    int find(int x){
        if (par[x] == -1) return x;
        else{
            par[x] = find(par[x]);
            return par[x];
        }
    }
    bool same(int x, int y){
        return find(x) == find(y);
    }
    int size(int x){
        return siz[find(x)];
    }
    void merge(int x, int y){
        x = find(x);
        y = find(y);
        if (x == y) return;
        if (siz[x] < siz[y]) swap(x,y);
        siz[x] += siz[y];
        par[y] = x;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N,M;
    cin>>N>>M;
    UnionFind uf(N);
    vector<bool>flag(N);
    vector<int>C(N);
    for(int i=0;i<M;i++){
        int u,v;
        cin>>u>>v;
        u--;
        v--;
        if(u==v)flag[u]=true;
        uf.merge(u,v);
        C[u]++;
        C[v]--;
    }
    vector<vector<int>>G(N);
    for(int i=0;i<N;i++){
        G[uf.find(i)].push_back(i);
    }
    int ans=0;
    for(auto v:G){
        if(v.empty())continue;
        if((int)v.size()==1&&!flag[v[0]])continue;
        ans++;
        vector<pair<int,int>>w;
        for(auto i:v)w.push_back(make_pair(C[i],i));
        sort(all(w));
        int a=0,b=0;
        for(auto i:w){
            if(i==w.front()){
                a+=max(0,-1-C[i.second]);
                b+=max(0,-C[i.second]);
            }else if(i==w.back()){
                a+=max(0,1-C[i.second]);
                b+=max(0,-C[i.second]);
            }else{
                a+=max(0,-C[i.second]);
                b+=max(0,-C[i.second]);
            }
        }
        ans+=min(a,b);
    }
    ans--;
    cout<<ans<<"\n";
}