#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
   long n,m,p;
    scanf("%ld%ld",&n,&m);
    p=n*m;
    printf("%ld",p-1);
    return 0;
}