#include <stdio.h>

int a[1005][1005], n, m, viz[1005], h, x, y;


void DFS(int nod)
{
	int i;
	viz[nod] = 1;
	for (i = 1; i <= n; i++) 
        if (!viz[i] && a[nod][i]) DFS(i);
}	

int main()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	scanf("%d %d",&n,&m);
	
	int i;
	
	for (i=1;i<=m;i++)
	{
		scanf("%d %d",&x,&y);
		a[x][y] = a[y][x] = 1;
	}
	
	
	for (i=1;i<=n;i++) if (!viz[i]) { 
                                     h++; 
                                     DFS(i);
                                     }
	
	printf("%d\n",h);
	return 0;
}