s = input()

while True:
    if s.count("3"):
        three = False
        t = ""
        for x in s:
            if three: t+="9"
            else:
                if x == "3":
                    three = True
                    t += "2"
                else:
                    t += x
        s = t
    else:
        n = int(s)
        if n%3:
            print(n)
            exit()
        n -= 1
        s = str(n)