Beautiful String Checker

You are given a string s. Your task is to check whether the string is "beautiful" or not.

A string is called beautiful if it satisfies the following two conditions:

• All characters in the string are distinct. This means for any two different indices i and j, we have s[i] ≠ s[j]. In mathematical notation, \(\forall i \neq j, s_i \neq s_j\).
• The absolute difference between the ASCII values of every two consecutive characters is exactly 1. That is, for every index \(i\) (with \(0 \leq i < n-1\)), \(|s_{i+1} - s_i| = 1\).

Note that an empty string is considered beautiful.

inputFormat

The input consists of a single line that contains the string s. The string can be empty or consist of lowercase/uppercase letters.

outputFormat

Output a single word: YES if the string is beautiful according to the conditions stated, and NO otherwise.

abcdef

YES