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 scanner = new Scanner(System.in);
		Long n = scanner.nextLong();
		Long m = scanner.nextLong();
		
		Long count = 0L;
		
		if(n == 1) {
			count = m -1;
		} else if (m == 1) {
			count = n -1;
		} else {
			count =((n-1) * m) +m-1; 
		}
		
		System.out.println(count);
		scanner.close();

	}
	
}