#include <iostream>

using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    int res = a * 2;
    if (c >= 2) {
        res += b * 2;
        c -= 2;
        res += 3;
        res += 3 * (c / 2);
    }
    cout << res << '\n';
}