Looking for a combinatorial problem definition

Question

We are given "N" pairs of parentheses, ie "N" opening parenthesis "(" and "N" closing parenthesis ")". We are asked to find the number of ways to make Sequence of 2N parentheses that are GOOD, i.e. we dont close before opening.

I need to find a definition for GOOD Sequences that i can use for the rest of the problem.

Answer 1

Catalan numbers!