import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int m = in.nextInt();
        int n = in.nextInt();
        if(n==1&&m==1){
            System.out.println(0);
        }else if(n==1){
            System.out.println(m-1);
        }else if(m==1){
            System.out.println(n-1);
        }else{
            System.out.println(n+m-2);
        }
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    }
}