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import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class ArraySearch {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int[] numbers = Arrays.stream(scanner.nextLine().split(",")).mapToInt(Integer::parseInt).toArray();

        List<String> result = new ArrayList<>();

        for (int num : numbers) {
            int index = Math.abs(num) - 1;
            if (numbers[index] > 0) {
                numbers[index] = -numbers[index];
            }
        }

        for (int i = 0; i < numbers.length; i++) {
            if (numbers[i] > 0) {
                result.add(String.valueOf(i + 1));
            }
        }
        System.out.println((String.join(",", result)));
    }
}