Let's denote a function f(x) in such a way: we add 1 to x, then, while there is at least one trailing zero in the resulting number, we remove that zero. For example, 

  * f(599) = 6: 599 + 1 = 600 → 60 → 6; 
  * f(7) = 8: 7 + 1 = 8; 
  * f(9) = 1: 9 + 1 = 10 → 1; 
  * f(10099) = 101: 10099 + 1 = 10100 → 1010 → 101. 



We say that some number y is reachable from x if we can apply function f to x some (possibly zero) times so that we get y as a result. For example, 102 is reachable from 10098 because f(f(f(10098))) = f(f(10099)) = f(101) = 102; and any number is reachable from itself.

You are given a number n; your task is to count how many different numbers are reachable from n.

Input

The first line contains one integer n (1 ≤ n ≤ 10^9).

Output

Print one integer: the number of different numbers that are reachable from n.

Examples

Input


1098


Output


20


Input


10


Output


19

Note

The numbers that are reachable from 1098 are:

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1098, 1099.
"""
- math -
from math import factorial
from math import gcd
from math import pi
large_p = 10**9 + 7
from itertools import accumulate # 累積和
from operator import mul
- other -
from collections import Counter
from itertools import combinations
from itertools import combinations_with_replacement
from itertools import permutations
from operator import itemgetter
from functools import reduce
- list -
from copy import deepcopy
from collections import deque
from heapq import heapify, heappop, heappush
- output -
p2d = lambda x: print(*x, sep="\n")
p2line = lambda x: print(*x, sep=" ")
print(*list1, sep="\n")
- input -
import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
= map(int, input().split())
= [tuple(map(int, input().split())) for _ in range(n)]
m = map(int, read().split()) /ab = zip(m, m) /for a, b in ab:
ps = [line.split() for line in readlines()] # inputの最後まで読んでしまうので注意。
n, k, *h = map(int, read().split())
- run -
sys.setrecursionlimit(10**6)
from time import sleep
"""
#ATC06

import sys
read = sys.stdin.read
readlines = sys.stdin.readlines
def main():
    def f(n):
        n += 1
        while n % 10 == 0:
            n //= 10
        return n
    num = int(input())
    nums = set()
    r = 0
    while True:
        if num in nums:
            break
        else:
            nums.add(num)
            r += 1
            num = f(num)
    print(r)

if __name__ == '__main__':
    main()