N = int(input())
result = 0
number = 0
for i in range(1,N+1):
if 5**i <= N:
number+=1
else:
break
for i in range(1,number+1):
result +=(N // (5**i))
print(result)
모범답안
def calc(n, v):
ans = 0
i = v
while i <= n:
ans += n//i
i *= v
return ans
n = int(input())
ans = calc(n, 5)
print(ans)