#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
long long int count1=0;



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