#include <bits/stdc++.h>
using namespace std;
ifstream f("dfs.in");ofstream g("dfs.out");
int n,m,viz[100005],nr,x,y;
typedef struct nod
{
    int x;
    nod *a;
}*pnod;
pnod v[100005];
void add(pnod &dest,int val)
{
	pnod p;
	p=new nod;
	p->x=val;
	p->a=dest;
	dest=p;
}
void dfs(int nod)
{
    pnod p;viz[nod]=1;
    for(p=v[nod];p!=NULL;p=p->a)if(!viz[p->x])dfs(p->x);
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>x>>y;
        add(v[x],y);add(v[y],x);
    }
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            nr++;
            dfs(i);
        }
    }
    g<<nr;
    return 0;
}