#include<fstream>
using namespace std;
ofstream g("dfs.out");

int i,j,n,m,*a[100001],x,y,p,q,viz[1000001];
void df(int x)
{
	//g<<x<<" ";
	viz[x]=1;
	for(int i=1;i<=a[x][0];i++)
		if(!viz[a[x][i]])
			df(a[x][i]);
}
int main()
{
	ifstream f("dfs.in");
	f>>n>>m;
	for(i=1;i<=n;i++)
	{
		a[i]=(int *)realloc(a[i],sizeof(int));
		a[i][0]=0;
	}
	while(f>>x>>y)
	{
		a[x][0]++;
		a[x]=(int *)realloc(a[x],(a[x][0]+1)*sizeof(int));
		a[x][a[x][0]]=y;
		a[y][0]++;
		a[y]=(int *)realloc(a[y],(a[y][0]+1)*sizeof(int));
		a[y][a[y][0]]=x;
	}
	int ok=0;
	for(i=1;i<=n;i++)
		if(!viz[i])
		{
			ok++;
			df(i);
		}
		g<<ok;
	return 0;
}