#include <fstream>
#include <vector>
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");
const int maxi=100005;
int n,m,cnt;
bool viz[maxi];
vector<int> a[maxi];
void DFS(int x)
{
    for(unsigned int i=0; i<a[x].size(); ++i)
        viz[a[x][i]]=1;
}
void citire()
{
    cin>>n>>m;
    for(int i=1; i<=m; ++i)
    {
        int x,y;
        cin>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for(int i=1; i<=n; ++i)
        if(viz[i]==0)
        {
            viz[i]=1;
            ++cnt;
            DFS(i);
        }
    cout<<cnt;
}
int main()
{
    citire();
    return 0;
}