/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
 
	 String s = "abcd";
 
		System.out.println(makeSmallestPalindrome(s));
	}
 
	static String makeSmallestPalindrome(String s) {
 
      int n = s.length();
 
      int start = 0;
 
      int end = s.length()-1;
 
      char [] str = s.toCharArray();
 
      while(start < end){
        if(str[start] != str[end] ){
 
          char small = str[start] < str[end] ? str[start] : str[end];
 
          str[start]=small;
          str[end] = small;
        }
        start++;
        end--;
 
      }
 
 
    return new String(str);
    }
}

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