#include <bits/stdc++.h>
using namespace std;
#define NMAX 100001

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m,viz[NMAX],nr;

vector<int>A[NMAX];

void read(){
    int x,y;
    fin>>n>>m;
    for(int i=1;i<=m;i++){fin>>x>>y;A[x].push_back(y);A[y].push_back(x);}
}

void DFS(int x){
viz[x]=1;
for(auto i:A[x]) if(!viz[i]) viz[i]++,DFS(i);
}

int main(){
    read();
    for(int i=1;i<=n;i++){
        if(!viz[i]) DFS(i),nr++;
    }
    fout<<nr;
    return 0;
}
/*
6 3
1 2
1 4
3 5
*/