// dfs- componente conexe...cu liste inlantuite

#include <cstdio>
#define N 100001

struct nod { int x; nod *n;};

nod *a[N];
int n, m;
bool use[N];

void read()
{
	freopen("dfs.in","r",stdin);
	scanf("%d %d\n", &n, &m);
	nod *t;
	int p, q;
	
	while(m--)
	{
		
		scanf("%d %d\n", &p, &q);
		t=new nod;
		t->x=q;
		t->n=a[p];
		a[p]=t;
		
		t=new nod;
		t->x=p;
		t->n=a[q];
		a[q]=t;
	}
}

inline void dfs(int n)
{
	use[n]=1;
	
	for(nod *i=a[n]; i; i=i->n)
		if(!use[i->x]) 
			dfs(i->x);
}

int main()
{
	read();
	int i,sol=0;
	
	for(i=1;i<=n;++i)
		if(!use[i])
		{
			++sol;
			dfs(i);
		}
	
	freopen("dfs.out","w",stdout);
	printf("%d\n", sol);
	
	return 0;
}