def has_two_occurrences(word):
    letter_count = {}
    for letter in word:
        if letter in letter_count:
            letter_count[letter] += 1
        else:
            letter_count[letter] = 1
 
    for letter, count in letter_count.items():
        if count == 2:
            return True
    return False
 
def main():
    try:
        while True:
            line = input()
            if has_two_occurrences(line):
                print(line)
    except EOFError:
        pass
 
main()

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