#include<iostream>
#include <fstream>
using namespace std; 
ifstream f("DFS.in");
int a[50][50],n,m,viz[50],i,j,x,y,k;
void citire() 
{ f>>n;
         for(i=1;i<=n;i++)
         for(j=1;j<=n;j++)
         a[i][j]=0;
         while(f>>x>>y)
         a[x][y]=a[y][x]=1;
         }
       
         void dfs(int nod)
{
 viz[nod]=1;
 for(int k=1;k<=n;k++)
      if(a[nod][k]==1 && viz[k]==0)
               dfs(k);  
                 
}

int main () 
{
    int nr=0; 
    citire (); 
    for (int k=1;k<=n;++k)
                if(viz[k]==0)
                    {
                    dfs(k);
                    ++nr;
                    }
                    
    cout<<nr<<endl; 
system ("pause");
return 0 ;
}