public static void Main()
int a1 = int.Parse(Console.ReadLine());
int b1 = int.Parse(Console.ReadLine());
Console.WriteLine(a1+b1);
Console.WriteLine(a1*b1);
Console.WriteLine(a1-b1);
Console.WriteLine(a1/b1);
Console.WriteLine(a1%b1);
double a = double.Parse(Console.ReadLine());
double b = double.Parse(Console.ReadLine());