#include <fstream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,nr,i,j,viz[100000];
vector <int> M[100000];
void dfs(int nod)
{
    viz[nod]=1;
    vector <int> :: iterator it=M[nod].begin(),sf=M[nod].end();
    for (;it!=sf;it++)
        if (viz[*it]==0)    dfs(*it);
}
int main()
{   f>>n>>m;
    for (i=1;i<=m;i++)
    {
        int x,y;
        f>>x>>y;
        M[x].push_back(y);
        M[y].push_back(x);
    }
    for (i=1;i<=n;i++)
        if (viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    g<<nr;
    g.close();
    return 0;
    return 0;
}