Detect Repeated Characters

You are given a string S that consists of lowercase English letters only. Your task is to determine whether the string contains any repeated characters. If there exists at least one character that appears more than once in the string, output YES; otherwise, output NO.

In mathematical terms, given a string \( S \) of length \( n \), we need to check whether \( \left|\{S[i]: 0 \leq i < n\}\right| \neq n \). If this inequality holds, then there exists some repeated character.

inputFormat

The input consists of a single line containing the string \(S\). You can assume that \(S\) contains only lowercase English letters and may be empty.

outputFormat

Output a single line. Print YES if the string contains any repeated characters, otherwise print NO.

hello

YES