#include <bits/stdc++.h>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
struct nod{int nr;nod *urm;}*a[100001];
int n,m,v[100001],nr;

void pune(int x,int y)
{
    nod *p=new nod;
    p->nr=y;
    p->urm=a[x];
    a[x]=p;
}

int muchie(int x, int y)
{
    nod *p=a[x];
    while(p)
    {
        if(p->nr==y)
            return 1;
        p=p->urm;
    }
    return 0;
}

void df(int k)
{
    v[k]=nr;
    nod *p=a[k];
    while(p)
    {
        if(!v[p->nr])
            df(p->nr);
        p=p->urm;
    }
}

int main()
{
    f>>n>>m;
    for(int i=1;i<=m;++i)
    {
        int x,y;
        f>>x>>y;
        pune(x,y);
        pune(y,x);
    }
    for(int i=1;i<=n;++i)
        if(!v[i])
            ++nr,df(i);
    g<<nr;
    return 0;
}