CF1099B Squares and Segments

Little Sofia is in fourth grade. Today in the geometry lesson she learned about segments and squares. On the way home, she decided to draw $ n $ squares in the snow with a side length of $ 1 $ . For simplicity, we assume that Sofia lives on a plane and can draw only segments of length $ 1 $ , parallel to the coordinate axes, with vertices at integer points. In order to draw a segment, Sofia proceeds as follows. If she wants to draw a vertical segment with the coordinates of the ends $ (x, y) $ and $ (x, y+1) $ . Then Sofia looks if there is already a drawn segment with the coordinates of the ends $ (x', y) $ and $ (x', y+1) $ for some $ x' $ . If such a segment exists, then Sofia quickly draws a new segment, using the old one as a guideline. If there is no such segment, then Sofia has to take a ruler and measure a new segment for a long time. Same thing happens when Sofia wants to draw a horizontal segment, but only now she checks for the existence of a segment with the same coordinates $ x $ , $ x+1 $ and the differing coordinate $ y $ . For example, if Sofia needs to draw one square, she will have to draw two segments using a ruler: After that, she can draw the remaining two segments, using the first two as a guide: If Sofia needs to draw two squares, she will have to draw three segments using a ruler: After that, she can draw the remaining four segments, using the first three as a guide: Sofia is in a hurry, so she wants to minimize the number of segments that she will have to draw with a ruler without a guide. Help her find this minimum number.

The only line of input contains a single integer $ n $ ( $ 1 \le n \le 10^{9} $ ), the number of squares that Sofia wants to draw.

Print single integer, the minimum number of segments that Sofia will have to draw with a ruler without a guide in order to draw $ n $ squares in the manner described above.