At a lemonade stand, each lemonade costs `$5`. Customers are standing in a queue to buy from you and order one at a time (in the order specified by bills). Each customer will only buy one lemonade and pay with either a `$5`, `$10`, or `$20` bill. You must provide the correct change to each customer so that the net transaction is that the customer pays `$5`.

Note that you do not have any change in hand at first.

Given an integer array `bills` where `bills[i]` is the bill the `ith` customer pays, return `true` if you can provide every customer with the correct change, or `false` otherwise.

Example 1:

    Input: bills = [5,5,5,10,20]
    Output: true
    Explanation:
    From the first 3 customers, we collect three $5 bills in order.
    From the fourth customer, we collect a $10 bill and give back a $5.
    From the fifth customer, we give a $10 bill and a $5 bill.
    Since all customers got correct change, we output true.

Example 2:

    Input: bills = [5,5,10,10,20]
    Output: false
    Explanation:
    From the first two customers in order, we collect two $5 bills.
    For the next two customers in order, we collect a $10 bill and give back a $5 bill.
    For the last customer, we can not give the change of $15 back because we only have two $10 bills.
    Since not every customer received the correct change, the answer is false.

Constraints:

- `1 <= bills.length <= 105`
- `bills[i]` is either `5`, `10`, or `20`.