It seems like the year of 2013 came only yesterday. Do you know a curious fact? The year of 2013 is the first year after the old 1987 with only distinct digits.

Now you are suggested to solve the following problem: given a year number, find the minimum year number which is strictly larger than the given one and has only distinct digits.
The single line contains integer *y* (1000 ≤ *y* ≤ 9000) — the year number.
n = str(int(input())+1)

def checker(n):
    a =''
    for char in n:
        if char not in a:
            a+=char
    if len(a)==4:
        return a
    else:
        n = str(int(n)+1)
        return checker(n)

print(checker(n))
