#include<stdio.h>
#include<vector>

using namespace std;

int sel[100002];
vector < vector < int> > muchii;

void df( int a)
{
	sel[a] = 1;
	for( int i = 0; i < muchii[a].size(); ++i)
	{
		if( sel[ muchii[a][i] ] == 0)
			df( muchii[a][i]);
	}
}

int main()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	
	
	int n,m;
	
	scanf("%d %d",&n,&m);
	vector < int > temp;
	for( int i = 0; i <= n; ++i)
	{
		muchii.push_back(temp);
	}
	
	for( long i = 1; i <= m; ++i)
	{
		int x,y;
		scanf("%d %d", &x, &y);
		muchii[x].push_back(y);
		muchii[y].push_back(x);
		
	}
	int sol = 0;
	for( int i = 1; i <= n; ++i)
	{
		if( sel[i] == 0)
		{
			sol++;
			df(i);
		}
	}
	printf("%d\n", sol);
	
	
	
	return 0;
}