#include <cstdio>
#include <vector>
#include <bitset>
#define NMax 100005
using namespace std;
bitset<NMax>Use;
vector<int>G[NMax];
int N,M,Sol;
void Read()
{
	freopen("dfs.in","r",stdin);
	scanf("%d%d",&N,&M);
	for(int i=1;i<=M;i++)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		G[x].push_back(y);
		G[y].push_back(x);
	}
}
void DFS(int Nod)
{
	Use[Nod]=1;
	for(unsigned int i=0;i<G[Nod].size();i++)
	{
		int Vecin=G[Nod][i];
		if(!Use[Vecin])
			DFS(Vecin);
	}
}
void Solve()
{
	for (int i=1;i<=N;i++)
	{
		if(!Use[i])
		{
			DFS(i);
			Sol++;
		}
	}
}
void Print()
{
	freopen("dfs.out","w",stdout);
	printf("%d\n",Sol);
}
int main()
{
	Read();
	Solve();
	Print();
	return 0;
}