Recurring Character

Given a lowercase alphabet string s, return the index of the first recurring character in it. If there are no recurring characters, return -1.

Constraints

• n ≤ 100,000 where n is the length of s

https://binarysearch.com/problems/Recurring-Character

Examples

Example 1

Input

• s = abcde

Output

• answer = -1

Explanation

No recurring characters in this string.

Example 2

Input

• s = aaaaa

Output

• answer = 1

Explanation

We want the first recurring character.

Example 3

Input

• s = abcda

Output

• answer = 4

Explanation

The a at index 4 is the first recurring character.

Solution