#include<stdio.h>
int n, m, v[2000][2000], x[2000], viz[2000], niv=1;
int df(int nod)
{
	int i;
	viz[nod]=1;
	for(i=1;i<=n;i++)
		if(v[nod][i]==1 && viz[i]==0)
			df(i);
}
int main()
{
	freopen("dfs.in", "r", stdin);
	freopen("dfs.out", "w", stdout);
	int i, k, s=0;
	scanf("%d%d", &n, &m);
	k=m*2;
	for(i=1;i<=k;i++)
		scanf("%d", &x[i]);
	for(i=1;i<=n;i+=2)
	{
		v[x[i]][x[i+1]]=1;
		v[x[i+1]][x[i]]=1;
		
	}
	for(i=1;i<=n;i++)
		if(viz[i]==0)
			
		{
			df(i);
			s++;
		}
	printf("%d", s);	
	return 0;
}