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

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