import sys

sys.setrecursionlimit(10**6)

N = [*input()]
size = len(N)

if all(n in ("4", "5") for n in N):
    print(*N, sep="")
    exit()

if ["4"] * size > N:
    print("5" * (size - 1))
    exit()

ans = []


def dfs(idx):
    n = int(N[idx])
    if n <= 3:
        return False
    elif n == 4:
        ans.append("4")
        res = dfs(idx + 1)
        if res == False:
            ans.pop()
            return False
    elif n == 5:
        ans.append("5")
        res = dfs(idx + 1)

        if res == False:
            ans.pop()
            ans.append("4")
            ans.extend(["5"] * (size - idx - 1))
    else:
        ans.extend(["5"] * (size - idx))

    return True


dfs(0)
print(*ans, sep="")