#include<cstdio>
#include<vector>
using namespace std;
#define lg 100010
vector < int > v[lg];
bool viz[lg];
int nr;
void dfs(int nod){
	viz[nod]=1;
	for(int i=0;i<v[nod].size();++i)
		if(!viz[v[nod][i]])
			dfs(v[nod][i]);
}
int main () {
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	
	int i,n,m,a,b;
	scanf("%d%d",&n,&m);
	for(i=1;i<=n;++i){
		scanf("%d%d",&a,&b);
		v[a].push_back(b);
		v[b].push_back(a);
	}
	for(i=0;i<n;++i)
		if(!viz[i]){
			dfs(i);
			++nr;
		}
	printf("%d\n",nr);
	return 0;
}