Competitions

# 2-Stage UOI Zhitomir 2010-2011 2010 1 st stream

# Side of the square

Find the integer length of the square, which can be obtained from the two rectangles a x b and c x d, cut them into rectangles and then folded so as to obtain the greatest possible area of the square.

## Input data

In one row there are four real numbers a, b, c, d. The area of each rectangle is less than 2·109.

## Output data

Derive a single number - the educated side of the square.

## Examples

Input example #1

1 2 3 4

Output example #1

3