#include<cstdio>
#include<vector>

using namespace std;

const int N = 1<<17;

vector<int> a[N];
bool viz[N];
int n , m , x , y , nr = 0 ;

void read()
{
	freopen ( "dfs.in" , "r" , stdin );
	freopen ( "dfs.out" , "w" , stdout ) ;
	
	scanf ( "%d %d"  , &n , &m ) ;
	
	for(int i=1 ; i<=m ; ++i )
	{
		scanf ( "%d %d" , &x , &y );
		a[x].push_back(y);
		a[y].push_back(x);
	}
}

void dfs(int x)
{
	viz[x] = true;
	
	for (size_t i=0 ; i<a[x].size() ; ++i )
	{
		y = a[x][i] ;
		if ( !viz[y] ) dfs(y);
	}
}
	

int main()
{
	read();
	
	for (int i=1 ; i<=n ; ++i )
	{
		if ( !viz[i] )
		{
			viz[i] = true;
			dfs(i) ;
			++ nr ;
		}
	}

	printf ( "%d\n" , nr );
	
	return 0;
}