#1110
num=input()
original=num
cnt=0
while True:
num=num.zfill(2)
new_num = str(int(num[0])+int(num[1]))
num = num[-1]+new_num[-1]
cnt+=1
if original == num:
break
print(cnt)
IzExMTAKbnVtPWlucHV0KCkKb3JpZ2luYWw9bnVtCmNudD0wCndoaWxlIFRydWU6CiAgICBudW09bnVtLnpmaWxsKDIpCiAgICBuZXdfbnVtID0gc3RyKGludChudW1bMF0pK2ludChudW1bMV0pKQogICAgbnVtID0gbnVtWy0xXStuZXdfbnVtWy0xXQogICAgY250Kz0xCiAgICBpZiBvcmlnaW5hbCA9PSBudW06CiAgICAgICAgYnJlYWsKcHJpbnQoY250KQ==