Valid Parentheses

Given a string input containing just the characters '(', ')', '{', '}', '[' and ']', determine if it is valid.

An input string is valid if:

1. Open brackets must be closed by the same type of brackets.
2. Open brackets must be closed in the correct order.

Example 1:

Input: input = "()"
Output: True

Example 2:

Input: input = "()[]{}"
Output: True

Example 3:

Input: input = "(]"
Output: False

Example 4:

Input: input = "([)]"
Output: False

Example 5:

Input: input = "{[]}"
Output: True

Constraints:

• The length of input is between 1 and 104.
• input consists of parentheses only '()[]{}'.