#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <stack>
#include <cassert>
using namespace std;

#define PRO "dfs"
void OpenFiles(int EVAL)
{
	if(EVAL)
	{
		char input[100] = PRO, output[100] = PRO;
		freopen(strcat(input, ".in"),"r",stdin);
		freopen(strcat(output,".out"),"w",stdout);
	} else
	{
		freopen("test.in","r",stdin);
		freopen("test.out","w",stdout);
	}
}

#define MAX 100001
#define INF 0xffffff

vector<int>g[MAX];
bool viz[MAX];
int n;

void dfs(int x)
{
	viz[x]=1;
	for(int i=0;i<g[x].size();i++)
		if(!viz[g[x][i]])dfs(g[x][i]);
}

int main(int argv,char *args[])
{
	OpenFiles(argv==0);	
	// start
	int m,x,y;
		scanf("%d %d",&n,&m);
		for(int i=1;i<=n;i++)
		{
			scanf("%d %d",&x,&y);
			g[x].push_back(y);
			g[y].push_back(x);
		}
		m=0;
		for(int i=1;i<=n;i++)
			if(!viz[i])
			{
				m++;
				dfs(i);
			}
		printf("%d\n",m);
	return 0;
}