927 B | 927 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
# sys.setrecursionlimit(10**7)
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline().rstrip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
MX = 1000001
a = [0] * MX
b = [0] * MX
a[2] = 1
a[4] = 2
b[5] = 1
for i in range(6, MX):
if i % 2 == 0:
a[i] = a[i // 2] + 1
if i % 5 == 0:
b[i] = b[i // 5] + 1
for i in range(1, MX):
a[i] += a[i - 1]
b[i] += b[i - 1]
tc = 1
while True:
n = ii()
if n == 0:
break
p(f"Case #{tc}: {min(a[n], b[n])}")
tc += 1
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()