package yukicoder;

import java.util.Scanner;

public class N445 {

	public static void main(String[] args)
	{
		Scanner sc=new Scanner(System.in);
		int A=sc.nextInt(),B=sc.nextInt();
		int f=50*A+(int)Math.floor(50*A/(0.8+0.2*B));
		System.out.println(f);
	}

}