#include <iostream>
#include <cstring>
using namespace std;

#define SIZE 300005
int arr[SIZE];

int main(){
    memset(arr, 0, sizeof(arr));

    int N;
    cin >> N;
    int a, b;
    while(cin >> a >> b){
        arr[a] ++;
        arr[b] ++;
    }

    int counter = 0;
    for(int i = 0; i < SIZE; ++i){
        if(arr[i] > 2){
            counter += arr[i] -2;
        }
    }
    cout << counter;

    return 0;
}