Swap alternate elements (1st ↔ 2nd, 3rd ↔ 4th, etc.).

Difficulty: Medium

Phase: 4 · Basic Arrays

XP Reward: 20 XP

Topics: Basic Arrays, Medium

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

Problem Description

Given N followed by N integers, swap alternate elements (1st with 2nd, 3rd with 4th, etc.) and print the array. 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: 4 1 2 3 4

Output: 2 1 4 3

Explanation: Sample execution for input 4 1 2 3 4