{"trustable":true,"prependHtml":"\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"panel_content\"\u003ePatrick Star find an oval.\u003cbr\u003e\u003cbr\u003eThe half of longer axes is on the x-axis with length $a$.\u003cbr\u003e\u003cbr\u003eThe half of shorter axes is on the y-axis with length $b$.\u003cbr\u003e\u003cbr\u003ePatrick Star plan to choose a real number $c$ randomly from $[0, b]$, after that, Patrick Star will get a rectangle :\u003cbr\u003e\u003cbr\u003e1. The four vertexes of it are on the outline of the oval.\u003cbr\u003e\u003cbr\u003e2. The two sides of it parallel to coordinate axis.\u003cbr\u003e\u003cbr\u003e3. One of its side is $y \u003d c$.\u003cbr\u003e\u003cbr\u003ePatrick Star want to know the expectations of the rectangle\u0027s perimeter.\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"The first line contain a integer $T$ (no morn than 10), the following is $T$ test case, for each test case :\u003cbr\u003e\u003cbr\u003eEach line contains contains two integer a, b ($0 \u0026lt; b \u0026lt; a \u0026lt; 10^5$). Separated by an white space."}},{"title":"Output","value":{"format":"HTML","content":"For each test case output one line denotes the expectations of the rectangle\u0027s perimeter .\u003cbr\u003e\u003cbr\u003eYou should keep exactly 6 decimal digits and ignore the remain decimal digits. \u003cbr\u003e\u003cbr\u003eIt is guaranted that the 7-th decimal digit of answer wont be 0 or 9."}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e1\r\n2 1\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e8.283185\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}