480: Locker doors
解法：
模拟操作即可
n = int(input())
s = [False for _ in range(n)]
for i in range(1, n + 1):j = [k for k in range(i, n + 1, i)]for k in j:s[k - 1] = not s[k - 1]
print(s.count(True))
解法：
模拟操作即可
n = int(input())
s = [False for _ in range(n)]
for i in range(1, n + 1):j = [k for k in range(i, n + 1, i)]for k in j:s[k - 1] = not s[k - 1]
print(s.count(True))