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