#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
vector <int> v[100002];
int n,m,i,j,x,y,nod,nrc;
bool viz[100002];
void dfs(int x)
{
    viz[x]=1;
    for(int i=0;i<v[x].size();i++)
        if(viz[v[x][i]]==0)
        dfs(v[x][i]);
}
int main()
{
    fin>>n>>m;
    for(i=1;i<=n;i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(viz[i]==0)
        {
            nrc++;
            dfs(i);
        }
        fout<<nrc;
    return 0;
}