import java.util.*;
class RemoveDuplicateCharatcersFromString 
{
    public static String removeDuplicates(String s) {
            StringBuilder build = new StringBuilder();
            for (int i = 0; i < s.length(); i++) {
            String st = s.substring(i, i + 1);
            if (build.indexOf(st) == -1) {
              build.append(st);
            }
            }
           return build.toString();
    }

    public static void main(String[] args) 
    {
        String str="Hello World";
        String newString=removeDuplicates(str);
        System.out.println(newString);      
    }
}