const bonAppetit = (bill, k, b) =>
    console.log(
      (bill.reduce((acc, cur) => acc + cur) - bill[k]) / 2 === b
        ? "Bon Appetit"
        : bill[k] / 2
);

   unset($bill[$k]);
    $total = array_sum($bill);
    $total = $total / 2;
  if($total == $b){
      die('Bon Appetit');
  }else{
      $actual = $b - $total;
      die((string)$actual);
  }

void bonAppetit(int bill_count, int* bill, int k, int b) {
    int AnnaBill = 0;
    int actualCost;
    int refund;
    
    for(int i=0; i<bill_count; i++){
        AnnaBill += bill[i];
    }
    
    AnnaBill = AnnaBill - bill[k];
    
    if(AnnaBill/2 == b){
        printf("Bon Appetit\n");
    }
    
    else{
        actualCost = AnnaBill / 2;
        refund = b - actualCost;
        printf("%d", refund);
    }
}

void bonAppetit(vector<int> bill, int k, int b) {
    int actual = (accumulate(bill.begin(),bill.end(), 0)-bill[k])/2;
    
    (actual<b)? cout<<b-actual:cout<<"Bon Appetit";
}

long sum = bill.stream().mapToInt(Integer::intValue).sum();
    sum-=bill.get(k);
    if (b-(sum/2)==0) {
        System.out.println("Bon Appetit");
    } else {
        System.out.println(b-(sum/2));
    }