#include <fstream>
#define M 100001
using namespace std;
ifstream f ("dfs.in");
ofstream g ("dfs.out");
struct nod{int x;nod*urm;};
 nod *L[M];
 nod*p;
 int i,j,k,n,m,x,y,nc;
 int viz[M];
void adauga(int i,int j)
{
  nod*p;
  p=new nod;
  p->x=j;
  p->urm=L[i];
  L[i]=p;
 }
void DFS(int j)
{
nod *p;
viz[j]=1;
p=L[j];
while(p){
    if(viz[p->x]==0)DFS(p->x);
    p=p->urm;
  }
}
int main()
{
  f>>n>>m;
  for(i=1;i<=n;i++)L[i]=0;
  for(i=1;i<=m;i++)
  {
    f>>x>>y;
    adauga(x,y);
    adauga(y,x);
  }
  for(i=1;i<=n;i++)
    if(viz[i]==0){nc++; DFS(i);}
  g<<nc;
  return 0;}