//#include<iostream>
#include <fstream>
using namespace std; 
ifstream cin("dfs.in");
ofstream cout("dfs.out"); 
int a[1005][1005],n,m,viz[1005],nr;
void citire() 
{ int x,y,i;
     cin>>n>>m;
         for(i=1;i<=m;++i)
        { cin>>x>>y;
         a[x][y]=a[y][x]=1;}
         }
       
         void dfs(int nod)
{
         int i;
 viz[nod]=1;
 for(int i=1;i<=n;++i)
      if(a[nod][i]==1 && viz[i]==0)
               dfs(i);  
                 
}

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