# from PIL import Image

# img = Image.open("./hoge.png")
# N,M = img.size
# d = []
# for i in range(N):
#     for j in range(M):
#         d.append(chr(img.getpixel((i,j))))
# with open("fuga.html",mode="w",encoding="utf-8") as f:
#     f.write("".join(d))

import sys, math
input = lambda: sys.stdin.readline()[:-1]
def MI(): return map(int, input().split())
inf = 10**18
sys.setrecursionlimit(10**7)  # Codeforcesでは350000程度に

def f(x):
    if x < 10: return 0
    res = 1
    for i in range(math.floor(math.log10(x))+1):
        res *= x//(10**i)%10
    return 1 + f(res)

print(f(int(input())))