Valid Usernames

words = input().split(', ')
ALLOWED = (ord('-'), ord('_'))

def sanitize(w: str):
    found = False
    if 3 <= len(w) <= 16:
        for i in w:
            i= ord(i.lower())
            if i in range(97, 123) or i in ALLOWED or i in range(48, 58):
                found = True
            else:
                found = False
                break
        if found:
            return w

for word in words:
    if sanitize(word):
        print(word)