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.
def unique(n):
    while:
        r=n%10
        set.append(r)
        n=n/10
        c++
    if len(set)==c:
        print(t)
        break
    else:
        unique(n+1)

num=int(input())
c=0
s=set[]
if n<=1987:
    print("2013")
else:
    n=num+1
    unique(n)