using System;

public class Program

{

    public static void Main()

    {int a=10;

     a++;

     Console.WriteLine(a);

     int b=5;

     b--;

     Console.WriteLine(b);

     double rad;

     Console.WriteLine(Math.PI);

     Console.WriteLine(Math.Abs(-5.5));

     Console.WriteLine(Math.Ceiling(3.78));

     Console.WriteLine(Math.Floor(2.55));

     Console.WriteLine(Math.Max(3,7));

     Console.WriteLine(Math.Min(3,-3));

     Console.WriteLine(Math.Sqrt(7.7));

     Console.WriteLine(Math.Pow(2.2,3));

     Console.WriteLine(Math.Round(3.5678,2));

     Console.WriteLine("Въведи радиус:");

     rad=double.Parse(Console.ReadLine());

     double s=Math.PI*rad*rad;

     double p=2*Math.PI*rad;

     Console.WriteLine("Лице={0}",s);

     Console.WriteLine("Периметър={0}",p);

    }

}