#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 long m,n;
    scanf("%lld%lld",&m,&n);
    long long results=m-1+(m*(n-1));
    printf("%lld\n",results);
    return 0;
}