#include <bits/stdc++.h>

using namespace std;

#define pb push_back
const int NMax = 1e+6 + 100;

vector<int> adj[NMax];
bool viz[NMax];
int dfs(int k)
{
    viz[k]=true;
    for(auto it=adj[k].begin();it!=adj[k].end();++it)
        if(!viz[*it])
            dfs(*it);
}
int main()
{
    int n,m,i,j,c=0;
    cin>>n>>m;
    while(m--)
    {
        cin>>i>>j;
        adj[i].pb(j),
        adj[j].pb(i);
    }
    for(int i=1;i<=n;i++){
      if(!viz[i])
        dfs(i),c++;
    }
    cout<<c<<'\n';
}