\includegraphics{https://static.e-olymp.com/content/d4/d422c342fbdda16a1205994648e8c02ea524ddbd.jpg} Two projectors of the round form form on a wall two spots, one - blue, and the second -- yellow color. To define the area of a spot of green color which will turn out at imposing two spots. \InputFile In the first line coordinates of the center of one spot contain: \textbf{X_1}, \textbf{Y_1} and its radius \textbf{R_1}, and in the second -- coordinates of the center of second spot \textbf{X_2}, \textbf{Y_2} and its radius \textbf{R_2}. (|\textbf{X_i}|, |\textbf{Y_i}|, \textbf{R_i} <= \textbf{10^6}) \OutputFile In one line a singular: the required area of a green spot deduced with accuracy of \textbf{3} signs after a decimal point, received by rules of mathematical calculations.