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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include<math.h>
#include<string.h>

int substr(char *t,const char *s,int pos,int len )
{
    if(pos < 0||len < 0||len > strlen(s))
        return -1;
    for(s += pos;*s!='\0' && len>0;len--)
        *t++ = *s++;
    *t = '\0';
    return 0;
}

int main(void){
    int N,k;
    char s[100];
    char t[100];
    char u[200];
    char r[200];

    scanf("%d",&N);
    scanf("%s",&s);
    scanf("%s",&t);
  
    for(k=0;k <= 2*N;k++){
        if(k%2==0){
            u[k]=s[k/2];
        }

        if(k%2==1){
            u[k]=t[(k-1)/2];
        }
    }
    
    substr(r,u,0,2*N);
  
    printf("%s",r);
  
    return 0;
}