import java.io.PrintStream;
import java.util.Scanner;

public class Touching
{
    public static void main(String[] args)
    {
        PrintStream output = System.out;
        Scanner input = new Scanner(System.in);

        output.print("Enter the radius of the larger circle: ");
        int bigRadius = input.nextInt();
        
        output.print("Enter the radius of the smaller circle: ");
        int smallRadius = input.nextInt();
        
        double dist1 = bigRadius + smallRadius +
                       2.0 * Math.sqrt(bigRadius * smallRadius);
        double dist2 = 2.0 * bigRadius;
        double dist = Math.max(dist1, dist2);
        
        output.print("The spanning distance is ");
        output.println(dist);
    }
}