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

int main() {
    long int a,b;
    scanf("%ld %ld",&a,&b);
    printf("%ld",((a*b)-1));
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}