#include <fstream>
#include <bitset>
using namespace std;
#define dim 1001
int mat[dim][dim];
int v[dim];
int n;

void dfs(int nod)
{
	if(!v[nod])
	{
		v[nod]=1;
		for(int i=1;i<=n;++i)
			if(mat[i][nod]&&!v[i])
				dfs(i);
	}
}


int main()
{
	ifstream fin("dfs.in");
	ofstream fout("dfs.out");
	
	
	int m,i ,a ,b;
	
	fin>>n >>m;
	
	for(i=1;i<=m;++i)
	{
		fin>>a >>b;
		mat[a][b]=1;
		mat[b][a]=1;
	}
	int contor=0;
	for(i=1;i<=n;++i)
	{
	
		if(v[i]==0)
		{
			++contor;
			dfs(i);
		}
	}
	
	fout<<contor;
	
	return 0;
}