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

int main() {

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