#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;
}