#include <bits/stdc++.h>

using namespace std;

ifstream fin("dfs.in");
ofstream  fout("dfs.out");
#define ll long long
const int maxn = 1e5;
const int maxg = -1e7;
vector<int> a[maxn + 2];
bitset<maxn + 2> visited;
int n, m;
void read(){
    fin >> n >> m;
    for(int i = 1; i <= m; ++i){
        int x, y; fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}
void dfs(int i){
    visited[i] = 1;
    for(auto x : a[i]){
        if(!visited[x])
            dfs(x);
    }
}
void solve(){
    int ans = 0;
    for(int i = 1; i <= n; ++i){
        if(!visited[i]) ans++, dfs(i);
    }
    fout << ans;
}
int main(){
    read();
    solve();


    return 0;
}
/*

*/