Problem:
Score : 200 points

Problem Statement

Given are strings s and t of length N each, both consisting of lowercase English letters.

Let us form a new string by alternating the characters of S and the characters of T, as follows: the first character of S, the first character of T, the second character of S, the second character of T, ..., the N-th character of S, the N-th character of T. Print this new string.

Constraints

1 \leq N \leq 100

|S| = |T| = N

S and T are strings consisting of lowercase English letters.

Input

Input is given from Standard Input in the following format:

N
S T

Output

Print the string formed.

Sample Input 1

2
ip cc

Sample Output 1

icpc

Sample Input 2

8
hmhmnknk uuuuuuuu

Sample Output 2

humuhumunukunuku

Sample Input 3

5
aaaaa aaaaa

Sample Output 3

aaaaaaaaaa

Solution in PHP7 (7.0.15) (judge verdict: Accepted)

<?php

$n = (int)trim(fgets(STDIN));
list($s, $t) = explode(" ", trim(fgets(STDIN)));
$sArr = str_split($s);
$tArr = str_split($t);

$str = '';
for ($i=0; $i<$n; $i++) {
    $str .= $sArr[$i].$tArr[$i];
}

echo $str."\n";