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

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