#include <stdio.h>

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