import java.util.*;
import java.math.*;

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        int n = sc.nextInt();
        int k = sc.nextInt();
        
        int ret = n*50+(int)Math.floor((n*50)/(0.8f+0.2f*k));
        
        System.out.println(ret);
    }
}