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