## \-\-- Day 7: Some Assembly Required \-\--

This year, Santa brought little Bobby Tables a set of wires and [bitwise
logic gates](https://en.wikipedia.org/wiki/Bitwise_operation)!
Unfortunately, little Bobby is a little under the recommended age range,
and he needs help [assembling the
circuit]{title="You had one of these as a kid, right?"}.

Each wire has an identifier (some lowercase letters) and can carry a
[16-bit](https://en.wikipedia.org/wiki/16-bit) signal (a number from `0`
to `65535`). A signal is provided to each wire by a gate, another wire,
or some specific value. Each wire can only get a signal from one source,
but can provide its signal to multiple destinations. A gate provides no
signal until all of its inputs have a signal.

The included instructions booklet describes how to connect the parts
together: `x AND y -> z` means to connect wires `x` and `y` to an AND
gate, and then connect its output to wire `z`.

For example:

-   `123 -> x` means that the signal `123` is provided to wire `x`.
-   `x AND y -> z` means that the [bitwise
    AND](https://en.wikipedia.org/wiki/Bitwise_operation#AND) of wire
    `x` and wire `y` is provided to wire `z`.
-   `p LSHIFT 2 -> q` means that the value from wire `p` is
    [left-shifted](https://en.wikipedia.org/wiki/Logical_shift) by `2`
    and then provided to wire `q`.
-   `NOT e -> f` means that the [bitwise
    complement](https://en.wikipedia.org/wiki/Bitwise_operation#NOT) of
    the value from wire `e` is provided to wire `f`.

Other possible gates include `OR` ([bitwise
OR](https://en.wikipedia.org/wiki/Bitwise_operation#OR)) and `RSHIFT`
([right-shift](https://en.wikipedia.org/wiki/Logical_shift)). If, for
some reason, you\'d like to *emulate* the circuit instead, almost all
programming languages (for example,
[C](https://en.wikipedia.org/wiki/Bitwise_operations_in_C),
[JavaScript](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_Operators),
or [Python](https://wiki.python.org/moin/BitwiseOperators)) provide
operators for these gates.

For example, here is a simple circuit:

    123 -> x
    456 -> y
    x AND y -> d
    x OR y -> e
    x LSHIFT 2 -> f
    y RSHIFT 2 -> g
    NOT x -> h
    NOT y -> i

After it is run, these are the signals on the wires:

    d: 72
    e: 507
    f: 492
    g: 114
    h: 65412
    i: 65079
    x: 123
    y: 456

In little Bobby\'s kit\'s instructions booklet (provided as your puzzle
input), what signal is ultimately provided to *wire `a`*?

To begin, [get your puzzle input](7/input).

Answer: