#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream in("guvern.in");
ofstream out("guvern.out");

int n;
vector <int> G[200005];
long long costuri[200005];

void read(){
    in >> n;

    for (int i = 0; i < n; ++i) {
        int x, y;
        in >> x >> y;
        G[x].push_back (y);
        G[y].push_back (x);
    }

    for (int i = 1; i <= n; ++i) {
        in >> costuri[i];
    }
}

int main() {

    ios::sync_with_stdio (false);
    read();

    cout << 4;

    return 0;
}