{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cstyle type\u003d\"text/css\"\u003e pre { text-align:left; font-family: \"Courier New\", Courier, monospace; font-size: 16px; white-space: pre; line-height:20px; text-indent: 0px; }\u003c/style\u003e\u003cdiv class\u003d\"pro_desc\"\u003e\n \u003cp\u003eFat brother and Maze are playing a kind of special (hentai) game in the clearly blue sky which we can just consider as a kind of two-dimensional plane. Then Fat brother starts to draw N starts in the sky which we can just consider each as a point. After he draws these stars, he starts to sing the famous song “The Moon Represents My Heart” to Maze.\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eYou ask me how deeply I love you, \u003c/p\u003e\n \u003cp\u003eHow much I love you? \u003c/p\u003e\n \u003cp\u003eMy heart is true, \u003c/p\u003e\n \u003cp\u003eMy love is true, \u003c/p\u003e\n \u003cp\u003eThe moon represents my heart. \u003c/p\u003e\n \u003cp\u003e…\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eBut as Fat brother is a little bit stay-adorable(呆萌), he just consider that the moon is a special kind of convex quadrilateral and starts to count the number of different convex quadrilateral in the sky. As this number is quiet large, he asks for your help.\u003c/p\u003e\n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv class\u003d\"pro_desc\"\u003e\n \u003cp\u003eThe first line of the date is an integer T, which is the number of the text cases.\u003c/p\u003e\n \u003cp\u003eThen T cases follow, each case contains an integer N describe the number of the points.\u003c/p\u003e\n \u003cp\u003eThen N lines follow, Each line contains two integers describe the coordinate of the point, you can assume that no two points lie in a same coordinate and no three points lie in a same line. The coordinate of the point is in the range[-10086,10086].\u003c/p\u003e\n \u003cp\u003e1 \u0026lt;\u003d T \u0026lt;\u003d100, 1 \u0026lt;\u003d N \u0026lt;\u003d 30\u003c/p\u003e\n\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv class\u003d\"pro_desc\"\u003e\n \u003cp\u003eFor each case, output the case number first, and then output the number of different convex quadrilateral in the sky. Two convex quadrilaterals are considered different if they lie in the different position in the sky.\u003c/p\u003e\n\u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e2\r\n4\r\n0 0\r\n100 0\r\n0 100\r\n100 100\r\n4\r\n0 0\r\n100 0\r\n0 100\r\n10 10\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003eCase 1: 1\r\nCase 2: 0\u003c/pre\u003e"}}]}