import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        
      Scanner scan = new Scanner(System.in);
      int m = scan.nextInt(); 
      int n = scan.nextInt();
      scan.close();
        
      System.out.println(minCuts(m, n));
    }
    
    
    public static int minCuts(int m, int n) {
		
		if (m <= 1 && n <= 1)
			return 0;
		
		int cuts = 1;
		
		int big = 0;
		int small = 0;
		
		if (m > n) {
			big = m;
			small = n;
		}
		else {
			big = n;
			small = n;
		}
		
		// cut along m
		if ((big & 1) > 0) {
			// it is odd
			cuts += minCuts(big/2, small);
			cuts += minCuts(big/2+1, small);
		}
		else {
			// it is even
			cuts += minCuts(big/2, small) * 2;
		}
		return cuts;
	}
}