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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.Scanner;
import java.lang.String;

public class Main {

    public static void main(String[] args) {
        int N, i, j;
        String S=null;
        String T=null;
        StringBuilder U= null;
        Scanner scan = new Scanner(System.in);
        N = scan.nextInt();
        for(i=0; i<N; i++)
        {
            while (S==null||S.length()!=N){
                S= scan.next();
            }

        }
        for(i=0; i<N; i++)
        {
            while (T==null||T.length()!=N){
                T= scan.next();
            }

        }
        for(i=0;i<N; i++){
            assert false;
            U.append(S.charAt(i)).append(T.charAt(i));
        }
        System.out.println(U);
    }
}