using System;

public class Program

{

    public static void Main()

    {

        int c=7;

        float p= 3.1416f;

        float r;

        float totalradio;

        r= c*c;

        totalradio= p * r;

        Console.WriteLine("el area de un circulo de {0} es de {1}", r, totalradio);

    }

}