For this Question: The question is super small and super simple.
You are given an integer n. Initially you have an empty string. You need to construct the string of length n with the following rules:
1. Insert the first character in the beginning of string, the second in the end, the third in the beginning, fourth in the end, and so on. 
2. The first character should be 'a', followed by 'b', 'c', and so on. 'z' will be followed by 'a'.The first and the only line of input contains a single number n.

Constraints
1 <= n <= 500000Output the generated string.Sample Input
4

Sample Output
cabd

Sample Input
30

Sample Output
caywusqomkigecabdfhjlnprtvxzbd

Explanation
In the first case the string transforms as follows: "" -> "a" -> "ab" -> "cab" -> "cabd", I have written this Solution Code: import java.io.*;
import java.util.*;



class Main {
	public static void main (String[] args) throws IOException{
		BufferedReader scan=new BufferedReader(new InputStreamReader(System.in));
		int n=Integer.parseInt(scan.readLine());
		char ch='a';
		boolean isFirst = true;
		StringBuilder sb = new StringBuilder();

		for(int i=0;i<n;i++)
		{
			if(isFirst) {
				sb.insert(0, (char)(ch + i%26));
			} else {
				sb.append((char) (ch + i%26));
			}
			isFirst = !isFirst;
		}
		System.out.print(sb.toString());


	}
}, In this Programming Language: Java, Now tell me if this Code is compilable or not?