Problems

# Side of the square

# 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**

In one row there are four real numbers **a**, **b**, **c**, **d**. The area of each rectangle is less than **2**·**10 ^{9}**.

**Output**

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

Input example #1

1 2 3 4

Output example #1

3