#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 int m,n;
    scanf("%ld%ld", &m, &n);
    printf("%ld", m*n-1);
    return 0;
}