#include <bits/stdc++.h>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    long long N,M; cin >> N >> M;
    map<long long,vector<long long>> Graph;
    while(N--){
        long long x,y; cin >> x >> y;
        Graph[x].push_back(y);
        Graph[y].push_back(x);
    }

    set<long long> already;
    int answer = 0;
    for(auto &[k,ign] : Graph){
        if(already.count(k)) continue;
        already.insert(k);
        int edge = 0,ver = 0;
        queue<long long> Q; Q.push(k);
        while(Q.size()){
            auto pos = Q.front(); Q.pop();
            ver++;
            for(auto &to : Graph[pos]){
                edge++;
                if(already.count(to)) continue;
                already.insert(to); Q.push(to);
            }
        }
        edge /= 2;
        answer += min(ver,edge);
    }
    cout << answer << "\n";
}