Unique Characters Check

In this problem, you are given a string ( s ) and you need to determine whether all the characters in ( s ) are unique. Formally, you should verify that for all indices ( i, j ) with ( i \neq j ) (where ( 0 \leq i, j < n ) and ( n ) is the length of ( s )), the characters satisfy ( s_i \neq s_j ). If the condition holds true, output YES; otherwise, output NO.

Note that an empty string is considered to have all unique characters.

inputFormat

The input consists of a single line containing the string \( s \). The string may be empty and will consist of ASCII characters.

outputFormat

Output a single line: YES if all characters in the string are unique, and NO otherwise.

algorithm

YES