#include<fstream>
#include<vector>
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");
const int N=1000001;
bool viz[N];
vector<int>a[N];
int n,m;
void citire()
{
    int i,x,y;
    in>>n>>m;
    for(i=1;i<=m;i++)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}
void dfs(int x)
{
    viz[x]=true;
    int y;
    for(int i=0;i<a[i].size();i++)
    {
        y=a[x][i];
        if(!viz[y])
            dfs(y);
    }
}
int main()
{
    citire();
    int nr=0;
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            dfs(i);
            nr++;

        }
    }
    out<<nr;
    return 0;
}