Four Square

Direct x = a and y = b divide the quadrilateral with vertices A(0, 0), B(0; y1), C(x1; y1), D(x1; 0) into four parts. Determine the square formed by the figures.

Input

In a single line through the space defined four integers: a, b, x1 and y1. All input data for the module does not exceed 100.

Output

Print the first area of a quadrilateral APQM, then through the gap - PBOQ, then through the gap - QOCK, and, finally, through the gap - MQKD. The results lead to three decimal.

Examples