/*
TASK: man
LANG: C++
*/
#define MAXN 15000

#include <iostream>
#include <queue>

using namespace std;

int a[MAXN+5][MAXN+5];
int m, n;
int br;

bool con (int u, int v)
         {
              queue<int> Q;
              bool used[MAXN+5]={0};
              
              if (u==v) return 1;
              
              Q.push(u);
              
              while (!Q.empty())
                    {
                                u=Q.front();
                                Q.pop();
                                
                                for (int i=0; i<=n; i++)
                                    if (a[u][i]&&!used[i])
                                       {
                                                if(i==v) return 1;
                                                Q.push(i);
                                                used[i]=1;
                                       }
                    }
              
              return 0;
         }

int main()
{
    scanf("%d", &m);
    
    for (int i=1; i<=m; i++)
        {
             int u, v;
             scanf("%d%d", &u, &v);
             
             if (u>n) n=u;
             if (v>n) n=v;
             
             if(!con(u,v)) { a[u][v]=a[v][u]=1; br++; }
        }
    
    printf("%d\n", br);
    
return 0;
}

