Having watched the last Harry Potter film, little Gerald also decided to practice magic. He found in his father's magical book a spell that turns any number in the sum of its digits. At the moment Gerald learned that, he came across a number *n*. How many times can Gerald put a spell on it until the number becomes one-digit?
The first line contains the only integer *n* (0 ≤ *n* ≤ 10<sup class="upper-index">100000</sup>). It is guaranteed that *n* doesn't contain any leading zeroes.
0
0
10
1
991
3
99
2
100
1
123456789
2
32
1
86
2
2
0
8
0
34
1
13
1
28
2
23
1
57
2
29
2
353869285
3
549548646
2
858893424
2
644818852
3
360322525
3
122937520
2
288403032
2
677257481
3
58059561
3
211288847
2
339900034079539584
2
784084029310269952
3
774730557264864000
3
478233807148352256
3
165646874056812544
3
477533739511673792
3
660119944377002240
3
448375218506078080
3
77213334785795616
3
165767221702271872
3
1
0
5
0
8
0
156161456146164104103460452045416165146141414651641564105461465156445621465146514562146145465165145145614561465145614561
3
9
0
import sys
import math
import random
import collections 
from collections import OrderedDict, defaultdict, deque

# define input function
def input():
    return sys.stdin.readline().rstrip()

def helper(n, currency):
    pass

def uscln(a, b):
    if (b == 0):
        return a;
    return uscln(b, a % b)

def brute_force(n, s):
    return

def random_compare():
    for n in range(1, 1000000001):
        ans = brute_force(n)
        # Code here
        l = 1
        r = n
        def check(mid):
            if (mid * (mid + 1)) // 2 <= n:
                return True
            return False
        
        while r - l > 1:
            mid = (l + r) // 2
            if check(mid):
                l = mid
            else:
                r = mid
        res = l
        #----------
        if ans != res:
            print(n)
            break
        else:
            print("OK")
        
# main function
def main():
    n = input()
    ans = 0
    while len(n) != 1:
        n = str(sum(map(int, list(n))))
        ans += 1
    print(ans)            
    
# run main function
if __name__ == '__main__':
    # t = int(input())
    t = 1
    while t:
        main()
        t -= 1