#include <cstdio>
#include <vector>
#define pb push_back
using namespace std;

vector <int> gr[200000];
vector <int> :: iterator it;

bool sel[200000];
void dfs (int x)
{
	vector <int> :: iterator it;
	sel[x]=true;
	for (it=gr[x].begin(); it!=gr[x].end(); it++)
		if (!sel[*it])
		{
			//sel[*it]=true;
			dfs(*it);
		}
}
int main ()
{
freopen ("dfs.in","r",stdin);
freopen ("dfs.out","w",stdout);
	int n,m,i,x,y,nc;
   
	scanf("%d%d", &n, &m);
	for (i=1;i<=m;i++)
	{
		scanf("%d%d", &x, &y);
		gr[x].push_back(y);
		gr[y].push_back(x);
    }
nc=0;
for (i=1;i<=n;i++)
	if (!sel[i])
	{
		nc++;
		dfs(i);
	}
printf("%d",nc);
return 0;
}