#include <stdio.h>



int a[1005][1005], n, m, viz[1005], cnt;



void citire()

{

	freopen("dfs.in","r",stdin);

	freopen("dfs.out","w",stdout);

	scanf("%d %d",&n,&m);

	int i, x, y;

	for (i = 1; i <= m; i++)

	{

		scanf("%d %d",&x,&y);

		a[x][y] = a[y][x] = 1;

	}

}



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()

{

	citire();

	int i;

	for (i = 1; i <= n; i++) if (!viz[i]) { cnt++; DFS(i);}

	printf("%d\n",cnt);

	return 0;

}