489. Bulb Switcher
MediumMath
n bulbs start off. In round i you toggle every i-th bulb, for i = 1..n. Print how many bulbs are on at the end.
Input format
One integer n
Output format
The number of bulbs on.
Example 1
Input
3
Output
1
Example 2
Input
0
Output
0
Constraints
0 ≤ n ≤ 10⁹
Read input from standard input and print the answer to standard output. Your code is judged against 5 test cases, most of them hidden.
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