#include<fstream>
using namespace std;
int n, m,c,s[100001];  
ifstream f("dfs.in",ios::in);
ofstream g("dfs.out",ios::out);
struct nod
{
    int info;
    nod *adr;
} ;
nod* v[100005];
 
void adaugare(nod*&dest, int nr)
{
    nod* p;
    p = new nod;
    p -> info = nr;
    p -> adr = dest;
    dest = p;
}
 
void citire()
{
      int i, x, y;
   
    f>>n;
    f>>m;
    for (i = 1; i <= m; i++)
    {
        f>>x;
        f>>y;
        adaugare(v[x], y);
        adaugare(v[y], x);
    }
}
 
void df(int nr)
{
    nod* p;
    s[nr] = 1;
    for (p = v[nr]; p != NULL; p = p -> adr) 
    if (s[p -> info]==0) 
    df(p -> info);
}  
 
int main()
{   int i;
    citire();
    for (i = 1; i <= n; i++) 
    if (s[i]==0)
     { c++;
      df(i);}
    g<<c;
    return 0;
}