// dfs-componente conexe vector<int> stl
using namespace std;
#include <cstdio>
#include <vector>
#define N 100001
#define pb push_back

vector<int> a[N];
int n,m;
bool use[N];

void read()
{
	freopen("dfs.in","r",stdin);
	scanf("%d %d\n", &n, &m);
	int p, q;
	
	while(m--)
	{
		scanf("%d %d\n", &p,&q);
		a[p].pb(q);
		a[q].pb(p);
	}
}

inline void dfs(int n)
{
	use[n]=1;
	
	for(vector<int>::iterator it=a[n].begin(); it!=a[n].end(); ++it)
		if(!use[*it])
			dfs(*it);
}

int main()
{
	read();
	int i, sol=0;
	
	for(i=1;i<=n;++i)
		if(!use[i])
		{
			++sol;
			dfs(i);
		}
	
	freopen("dfs.out","w",stdout);
	printf("%d\n", sol);
	return 0;
}