Problem:
Score : 200 points

Problem Statement

You are given a string s consisting of lowercase English letters. Extract all the characters in the odd-indexed positions and print the string obtained by concatenating them. Here, the leftmost character is assigned the index 1.

Constraints

Each character in s is a lowercase English letter.

1≤|s|≤10^5

Input

The input is given from Standard Input in the following format:

s

Output

Print the string obtained by concatenating all the characters in the odd-numbered positions.

Sample Input 1

atcoder

Sample Output 1

acdr

Extract the first character a, the third character c, the fifth character d and the seventh character r to obtain acdr.

Sample Input 2

aaaa

Sample Output 2

aa

Sample Input 3

z

Sample Output 3

z

Sample Input 4

fukuokayamaguchi

Sample Output 4

fkoaaauh

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
int main()
{
    int i=0,j=0,l;
    char s[100002],odd[100002];
    scanf("%s",s);
    l=strlen(s);
    for(i=0; i<l; i++)
    {
        if(s[i]>='a' && s[i]<='z')
        {
            if(i%2==0)
            {
                odd[j++]=s[i];
            }
        }
        else
        {
            return 0;
        }
    }
    printf("%s\n",odd);
    return 0;
}