#include <iostream>
using namespace std;

int f(int a)
{
return a * a;
}
int f (int a, int b = 0)
{
return a * b;
}
int main()
{
cout << f(10, 2);  
cout << f(10);
// ??? ??????? f(int, int) ??? f(int)???
return 0;
    }