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

public class Solution {

    public static void main(String[] args) {
      Scanner scan = new Scanner(System.in);
      long x = scan.nextLong();
      long y = scan.nextLong();
      System.out.println(x * y - 1);
      //System.out.println(cutSquare(x,y));
        
    }
  public static int cutSquare(int x, int y) {
    System.out.println("Cutsquare run on (" + x + ", " + y + ")");
    int retVal;
    if(x == 1) {
      return y-1;
    }
    if(y == 1) {
      return x-1;
    }
    if(x > y) {
      if((x % 2) == 0) {
        retVal = 1 + (cutSquare(x/2, y) * 2);
      }
      else {
        retVal = 1 + cutSquare(x/2, y) + cutSquare(x/2 + 1, y);
      }
    }
    else {
      if((y % 2) == 0) {
        retVal = 1 + (cutSquare(x, y/2) * 2);
      }
      else {
        retVal = 1 + cutSquare(x, y/2) + cutSquare(x, y/2 + 1);
      }
    }
    System.out.println("Returning: " + retVal);
    return retVal;
  }
}