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

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