import java.util.*;
    import java.util.ArrayList;
    import java.util.Scanner;


    public class Main
    {
        static String removeDuplicateElements(char str[], int n)
        {
            // Used as index in the modified string
            int index = 0;

            // Traverse through all characters
            for (int i = 0; i < n; i++)
            {

                // Check if str[i] is present before it
                int j;
                for (j = 0; j < i; j++)
                {
                    if (str[i] == str[j])
                    {
                        break;
                    }
                }

                // If not present, then add it to
                // result.
                if (j == i)
                {
                    str[index++] = str[i];
                }
            }
            return String.valueOf(Arrays.copyOf(str, index));
        }

        // Driver code

            public static void main(String[] args) {
                Scanner scanner = new Scanner(System.in);
                String input = scanner.nextLine();
                char str[] = input.toCharArray();
                int n = str.length;
                System.out.println(removeDuplicateElements(str, n));
            }
        }