/***************************************************************************************
*   FILE NAME:  Cutting Paper Squares.cpp
*
*   PURPOSE:
*
*   @author: Md. Arafat Hasan Jenin
*   EMAIL:  OpenDoor.Arafat@gmail.com
*
*   DEVELOPMENT HISTORY:
*       Date        Change      Version     Description
* ------------------------------------------------------------------------
*   18 Oct 16      New         1.0         Completed,Accepted
**************************************************************************************/

#include <stdio.h>

int main() {

    long long m, n;

    scanf("%lli %lli", &m, &n);
    printf("%lli\n", (m*n)-1);

    return 0;
}