#include<fstream>
#include<vector>
#include<bitset>
using namespace std;
ifstream cin("dfs.in");
ofstream cout("dfs.out");
vector<int> a[100001];
bitset<100001> b;
void A(int i)
{
    b[i]=1;
    for(int j:a[i])
        if(!b[j])
            A(j);
}
int main()
{
    int c=0,m,n;
    for(cin>>n>>m;m--;) {
        int i,j;
        cin>>i>>j,a[i].push_back(j),a[j].push_back(i);
    }
    for(int i=1;i<=n;++i)
        if(!b[i])
            A(i),++c;
    return cout<<c,0;
}