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); long n = in.nextInt(); long m = in.nextInt(); long x=Math.min(m*(n-1)+(m-1),n*(m-1)+(n-1)); System.out.println(x); } }