import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	double c = sc.nextInt();
    	double d = sc.nextInt();
    	double left = 0;
    	double right = Math.min(c / 3 * 4, d * 4);
    	for (int i = 0; i < 1000000; i++) {
    	    double m1 = (left * 2 + right) / 3;
    	    double m2 = (left + right * 2) / 3;
    	    double r1 = m1 * 1000 + Math.min((c - m1 * 3 / 4) / 2 * 7, (d - m1 / 4) / 5 * 7) * 2000;
    	    double r2 = m2 * 1000 + Math.min((c - m2 * 3 / 4) / 2 * 7, (d - m2 / 4) / 5 * 7) * 2000;
    	    if (r1 < r2) {
    	        left = m1;
    	    } else {
    	        right = m2;
    	    }
    	}
    	System.out.println(right * 1000 + Math.min((c - right * 3 / 4) / 2 * 7, (d - right / 4) / 5 * 7) * 2000);
	}
}