AT_abc389_d [ABC389D] Squares in Circle

On the two-dimensional coordinate plane, there is an infinite tiling of $ 1 \times 1 $ squares. Consider drawing a circle of radius $ R $ centered at the center of one of these squares. How many of these squares are completely contained inside the circle? More precisely, find the number of integer pairs $ (i,j) $ such that all four points $ (i+0.5,j+0.5) $ , $ (i+0.5,j-0.5) $ , $ (i-0.5,j+0.5) $ , and $ (i-0.5,j-0.5) $ are at a distance of at most $ R $ from the origin.

The input is given from Standard Input in the following format: > $ R $

Print the answer.

### Sample Explanation 1 There are a total of five squares completely contained in the circle: the square whose center matches the circle’s center, plus the four squares adjacent to it. ### Constraints - $ 1 \leq R \leq 10^{6} $ - All input values are integers.