{"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\"\u003e You just got your year-end bonus. As you had a lot of money, you decided to take your family to the United States for a twenty-day self-driving travel. One day, when you were driving on the Great Plains, you found you had left highway by accident. After checking your GPS, you realized that you were now D (0 \u0026lt; D \u0026lt;\u003d 1000) miles from the highway. The highway is straight and extends infinitely. When you are driving outside the highway, your maximum speed is v0 mph, but on the highway you can move in a maximum speed of v1 mph (200 \u0026gt;\u003d v1 \u0026gt; 1.2 v0 \u0026gt; 0). It took no time to get on or off the highway. Suddenly, it came to your mind that there was a region inside which any point can be reached within T (0 \u0026lt; T \u0026lt;\u003d 1000) hours. You wanted to know area of this region. \u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":" Input contains no more than 50 test cases.\u003cbr\u003e\u003cbr\u003e Each test case is a single line containing 4 integers v0, v1, D and T, as above mentioned."}},{"title":"Output","value":{"format":"HTML","content":" For each test case, output your answer in a line with the case number, follow the format in sample. Its unit should be square mile. Your answer will be accepted if its absolute or relative error is less than 10-6.\u003cbr\u003e\u003cbr\u003e This problem is special judged."}},{"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\u003e5 10 10 10\r\n5 20 10 10\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eCase 1: 9360.97707377\r\nCase 2: 14873.82733943\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Hint","value":{"format":"HTML","content":"You should print a blank after \":\" in the output.\u003cbr\u003e"}}]}