# include <cstdio>
# include <vector>
# define nmax 100001
using namespace std;
int x,y,n,m,viz[nmax],nr;
vector <int>G[nmax];
inline void dfs(int x)
{
    int i;
    viz[x]=1;
    for(i=0;i<G[x].size();++i)
        if(!viz[G[x][i]])
            dfs(G[x][i]);
}
int main()
{
    int i;
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;++i)
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);G[y].push_back(x);
    }
    for(i=1;i<=n;++i)
        if(!viz[i])
        {
            dfs(i);
            ++nr;
        }
    printf("%d\n",nr);
    return 0;
}