Find a matching key in a list and output the value associated with it.

Input parameters:

1. Ks → List of keys to search in.
2. Vs → List of associated values, one for each key.
3. Se → Key to search for.

Output parameters:

1. Vl → Value associated with the found key.
2. Ix → Index of the found key, or -1 if no key matched the search.