function bonAppetit(bill, k, b) {
    let totalBill = 0
    let partialBill = 0
    bill.forEach(value =>{
        totalBill += value
    })
    partialBill = (totalBill - bill[k])/2
    
    if (b- partialBill == 0 ){
        console.log("Bon Appetit")
    } else{
        console.log(b- partialBill)
    }
}