#include <iostream>
#include <vector>

using namespace std;

int p[300001]{};

int main() {

    int n, c = 0, a, i;
    cin >> n;

    n <<= 1;
    for (i = 2; i < n; ++i) {
        cin >> a;
        ++p[a];
        if (p[a] > 2)
            ++c;
    }

    cout << c << '\n';

    return 0;
}