---

numbers = input().split()
digit_count = {}

for number in numbers:
    for digit in number:
        if digit in digit_count:
            digit_count[digit] += 1
        else:
            digit_count[digit] = 1

max_count = max(digit_count.values())
result = [digit for digit, count in digit_count.items() if count == max_count]
result.sort()

print(' '.join(result))