A twodimensional rectangular cup full of (two-dimensional) water is inclined a little bit.Your task is to calculate how much water pours out.

Each line of the input file describes one test case. The lines contain three integers w, h and α ( 0 < w, h < 1000, 0 <= α <= 90 ):the width and the height of the cup and the angle by which the cup is inclined. The input is terminated by a line containing three zeros. This line should not be processed.

For each test case output a line containing only one number the amount of water poured out. Print the number exact to two digits to the right of the decimal point.

Mid-Central European Regional Contest 1999, Practice