#include<fstream>
#define Max 200001

using namespace std;

int t[2][Max],pus[Max],start[Max],m,n,p;
void read()
{
	ifstream fin("dfs.in");
	
	int i,k=0,x,y;
	
	fin>>n>>m;
	
	for(i = 1; i <= m; i++)
	{
		fin>>x>>y;
		k++;
		t[0][k] = y;
		t[1][k] = start[x];
		start[x] = k;
		k++;
		t[0][k] = x;
		t[1][k] = start[y];
		start[y] = k;
	}
	
	fin.close();
}
void dfs(int k)
{
	int nod;
	pus[k] = 1;
	nod = start[k];
	while(nod)
	{
		if(pus[t[0][nod]] == 0)
			dfs(t[0][nod]);
		nod = t[1][nod];
	}
}
int main()
{
	read();
	int i;

	ofstream fout("dfs.out");

	for(i = 1; i <= n; i++)
		if(!pus[i])
		{
		   dfs(i);
		    p++;
		}
	fout<<p<<" ";

fout.close();

return 0;

}