#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 */  
    unsigned long long n,k,a;
    scanf("%lld %lld",&n,&k);
    a=n*k-1;
    printf("%lld",a);
    return 0;
}