#include <iostream>
using namespace std;

int add ( // ADD CODE HERE
};

int main ()
{
    cout << add () << endl;
    cout << add (1) << endl;
    cout << add (1,2) << endl;
    cout << add (1,2,3) << endl;
    cout << add (1,2,3,4) << endl;
    return 0;
}