#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
#define NMAX 100010
using namespace std;

vector<int> v[NMAX];
int M, N, i, k, x, y;
bool viz[NMAX];

void read(void)
{
	freopen("dfs.in", "r", stdin);
	scanf("%d%d", &N, &M);
	
	for(i = 1; i <= M; ++i)
	{
		scanf("%d%d", &x, &y); 
		v[x].push_back(y);
		v[y].push_back(x);
	}
	
	fclose(stdin);
		
}
void DFS(int poz)
{
	vector<int>::iterator i;
	
	viz[poz] = 1;
	for(i = v[poz].begin(); i != v[poz].end(); ++i)
		if(viz[*i] == 0)
			DFS(*i);

}
void solve(void)
{
	for(i = 1; i <= N; ++i)
		if(!viz[i])
			DFS(i), ++k;
		
}
void print(void)
{
	freopen("dfs.out", "w", stdout);
	printf("%d\n", k);
	
	fclose(stdout);
}
int main(void)
{
	read();
	solve();
	print();
	
	return 0;
}