Remove Consecutive Duplicate Words

You are given a string consisting of multiple words separated by spaces. Your task is to remove any word that is immediately repeated. In other words, if a word appears consecutively, only the first occurrence should remain.

For example, given the input hello hello world, the output should be hello world. The same rule applies to any sequence of consecutive duplicate words.

Note: Words are case-sensitive, meaning that Hello and hello are considered different.

The problem can be formally stated as follows:

Given a string \( S = w_1 \; w_2 \; ... \; w_n \) where each \( w_i \) represents a word, construct a new string \( S' \) such that for every \( i (2 \leq i \leq n) \), if \( w_i = w_{i-1} \) then \( w_i \) is omitted from \( S' \).

inputFormat

The input consists of a single line containing a string. The string is made up of words separated by spaces. The input is provided via standard input (stdin).

outputFormat

Output a single line, via standard output (stdout), which is the modified string after removing all consecutive duplicate words.

hello hello world

hello world