publicint Sum(int a, int b)
        {
            return a + b;
        }
 
        publicdouble Sum(double a, double b)
        {
            return a + b;
        }
        publicint Sum(int a, int b)
        {
            return Sum(a, b, 0);
        }
 
        publicint Sum(int a, int b, int c)
        {
            return a + b + c;
        }