// Arup Guha
// 7/13/04
// Solution to 2004 BHCSI Farmer program.

import java.io.*;
import java.text.DecimalFormat;

public class Farmer {

  public static void main(String[] args) throws IOException {

    BufferedReader stdin = new BufferedReader
				(new InputStreamReader(System.in));

    // Get the user input.
    System.out.println("How long is the fence you bought?");
    int length = Integer.parseInt(stdin.readLine());
    System.out.println("What is the price of the fence per foot?");
    double unitcost = Double.parseDouble(stdin.readLine());
    System.out.println("How much do you earn for growing 1 sq. ft. of corn?");
    double unitprofit = Double.parseDouble(stdin.readLine());
    

    // Calculate the radius of the plot, and then its area.
    double radius = length/(2*Math.PI);
    double area = Math.PI*Math.pow(radius, 2);

    // Calculate the net profit: corn profit - fence cost.
    double netprofit = unitprofit*area - unitcost*length;

    // Use this to format output values to two decimal places.
    DecimalFormat money = new DecimalFormat("0.00");;
    
    // Check to see if Kit made money.
    if (netprofit >= 0) {
      System.out.print("Farmer Kit will earn $"+money.format(netprofit));
      System.out.println(" growing corn this year.");
    }
 
    // Output for when Kit lost money.
    else {
      System.out.print("Farmer Kit will lose $"+money.format(-netprofit));
      System.out.println(" growing corn this year.");
    }

  }
}