{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eA river flows down the plain along the line \u003ci\u003ey\u003c/i\u003e \u003d 0. There are trees growing in the plain to the both sides of the river, but not on the river itself. A dam is positioned on the river in the point (0,0). It is necessary to make two matching photos of the two river-sides\r\nfrom the dam. The photos are considered matching if the arrangement of the trees on them match (only the horizontal arrangement is considered, not the distance to the trees).\u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eIf a tree is obscured with another one, the tree isn\u0027t present in the photo. No two trees occupy one point. Sizes of the photo-camera and the trees are negligible.\u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eThe photographing occurs in the following way: first a camera is used whose spanning angle is arbitrary close to 180 degrees (the photo-film\r\nis a line, and trees in front of it are centrally projected onto the film, center is point (0,0)); then a segment with trees from one river-side only is cut out of the film, and scaled arbitrarily.\u003c/div\u003e\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eEach line of the input, except the last one, contains the coordinates of the trees (two integers from −20000 to 20000). The number of the trees doesn\u0027t exceed 10\u003csup\u003e5\u003c/sup\u003e.\r\n\u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eThe last line contains two zeros.\u003c/div\u003e\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eThe output must contain a single number, being the maximum number of trees on two matching photos of the two river-sides.\u003c/div\u003e\u003c/div\u003e"}},{"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\u003e-1 1\r\n0 1\r\n2 1\r\n3 1\r\n7 2\r\n3 -2\r\n1 -1\r\n0 -1\r\n0 -5\r\n-4 -2\r\n-3 -1\r\n0 0\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e4\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cbr\u003e\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\u003e0 1\r\n1 1\r\n2 1\r\n-3 -1\r\n-2 -2\r\n-1 -3\r\n0 0\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e3\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}