#include<iostream>
#include<stdio.h>
#include<vector>
#include<stack>
using namespace std;
vector<int> a[100010];
short ut[100010];
int x,y,nr;
int main()
{
	freopen("dfs.in","r",stdin);
	freopen("dfs.out","w",stdout);
	int i,n,m;
	scanf("%d%d",&n,&m);
	for(i=1;i<=m;i++)
	{
		scanf("%d%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	vector<int> ::iterator it;
	stack<int> st;
	for(i=1;i<=n;i++)
		if(!ut[i])
		{
			nr++;
			st.push(i);
			while(!st.empty())
			{
				int nod=st.top();
				for(it=a[nod].begin();it!=a[nod].end();it++)
					if(!ut[*it])
						st.push(*it);
				if(!ut[nod])
					ut[nod]=1;
				else
					st.pop();
			}
		}
	printf("%d\n",nr);
	return 0;
}