#include<cstdio>
#include<algorithm>
using namespace std;
const int NMAX=1e5+5;
vector <int> g[NMAX];
bool viz[NMAX];
void dfs(int nod)
{
    viz[nod]=1;
    for(int i=0; i<g[nod].size(); ++i)
      if(!viz[g[nod][i]])
        dfs(g[nod][i]);
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m;
    scanf("%d%d",&n,&m);
    for(int i=1; i<=n; ++i)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    int num=0;
    for(int i=1; i<=n; ++i)
    {
        if(!viz[i])
        {
            num++;
            dfs(i);
        }
    }
    printf("%d\n",num);
    return 0;
}