Keep only the first occurrence of each character.

Difficulty: Hard

Phase: 5 · Strings

XP Reward: 30 XP

Topics: Strings, Hard

Supported Languages: Python, JavaScript, C, C++, Java

Problem Description

Keep only the first occurrence of each character in a string and print. Input Format: Read input from standard input (stdin). Output Format: Print the result to standard output (stdout).

Constraints

-10^9 <= N <= 10^9

Examples

Example 1

Input: programming

Output: progami

Explanation: Sample execution for input programming