#include<bits/stdc++.h> 
using namespace std; 
const int maxn = 1e5 +5; 
int a[maxn], b[maxn], c[maxn]; 
bool u[maxn]; 
 
int main(){ 
 ios_base::sync_with_stdio(0); 
 cin.tie(0); 
 cout.tie(0); 
  
 int n; 
 cin>>n; 
  
 map <int, int> m; 
 set <int> s; 
  
 for(int i=1; i<=n; i++){ 
  cin>>a[i]>>b[i]; 
  m[a[i]]++; 
  m[b[i]]++; 
 } 
  
 for(int i=1; i<=n; i++){ 
  int v1 = a[i], v2 = b[i]; 
   
  if(v1==v2){ 
   c[i] = v1; 
   u[v1] = 1; 
  } 
  else if(!u[v1] && u[v2]){ 
   c[i] = v1; 
   u[v1] = 1; 
  } 
  else if(u[v1] && !u[v2]){ 
   c[i] = v2; 
   u[v2] = 1; 
  } 
  else if(!u[v1] && !u[v2]){ 
   /* 
   4 4  
   1 1 
   2 5 
   1 1 
   */ 
   int left1 = m[v1] - 1; 
   int left2 = m[v2] - 1; 
    
   if(left1 < left2){ 
    c[i] = v1; 
    u[v1] = 1; 
   } 
   else{ 
    c[i] = v2; 
    u[v2] = 1; 
   } 
  } 
     else{ 
      c[i] = v1; 
  } 
   
  m[v2]--; 
  m[v1]--; 
   
  s.insert(c[i]); 
 } 
  
  
 cout<<s.size(); 
  
}