import java.util.Scanner;

import java.lang.Math;

import static java.lang.System.*;

class SafeBlastDistance{

    public static void main(String[] args){


        double CCLF, ED, FOS, SBD, SD, D, CL, SL;

            Scanner scanner = new Scanner(System.in);

                System.out.print("Charge length (m): ");
                        CL = scanner.nextDouble();

                System.out.print("Stemming length (m): ");
                        SL = scanner.nextDouble();

                System.out.print("Borehole diameter (mm): ");
                        D = scanner.nextDouble();

        CCLF = 1000 * CL / D;

        ED = 1.2;

        FOS = 2.0;

    SBD = SL + 0.0005 * CCLF * D /  0.00923* CCLF * Math.pow(D, 3) * ED; Math.pow(SBD, 0.333);

    SD = FOS * 11 * Math.pow(SBD, -2.167) * Math.pow( D, 0.667);

        System.out.println( "Safe Blast Distance = " + SD );

    }
}