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. Yo
        int newM=m-m/2;
        int newN=n-n/2;
        ur class should be named Solution. */
        
        
        
		Scanner s=new Scanner(System.in);
		long n=s.nextLong();
		long m=s.nextLong();
        
        
         long out=0;
            if(n==1)
                out= m-1;
        
            if(m==1)
                out= n-1;
        
        
           long row=(n-1)+(m-1)*n;
            long col=m-1+(n-1)*m;
        
            if(row>col)
                out=col;
            else
            out=row;
        
      System.out.println(out);
        
            
   
    }
}