{"problem":{"name":"A. Find Extra One","description":{"content":"You have _n_ distinct points on a plane, none of them lie on _OY_ axis. Check that there is a point after removal of which the remaining points are located on one side of the _OY_ axis.","description_type":"Markdown"},"platform":"Codeforces","limit":{"time_limit":1000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"CF900A"},"statements":[{"statement_type":"Markdown","content":"You have _n_ distinct points on a plane, none of them lie on _OY_ axis. Check that there is a point after removal of which the remaining points are located on one side of the _OY_ axis.\n\n## Input\n\nThe first line contains a single positive integer _n_ (2 ≤ _n_ ≤ 105).\n\nThe following _n_ lines contain coordinates of the points. The _i_\\-th of these lines contains two single integers _x__i_ and _y__i_ (|_x__i_|, |_y__i_| ≤ 109, _x__i_ ≠ 0). No two points coincide.\n\n## Output\n\nPrint \"_Yes_\" if there is such a point, \"_No_\" — otherwise.\n\nYou can print every letter in any case (upper or lower).\n\n[samples]\n\n## Note\n\nIn the first example the second point can be removed.\n\nIn the second example there is no suitable for the condition point.\n\nIn the third example any point can be removed.","is_translate":false,"language":"English"},{"statement_type":"Markdown","content":"你平面上有 #cf_span[n] 个互不相同的点，且没有任何一个点位于 #cf_span[OY] 轴上。请判断是否存在一个点，将其移除后，剩余的点全部位于 #cf_span[OY] 轴的同一侧。\n\n第一行包含一个正整数 #cf_span[n]（#cf_span[2 ≤ n ≤ 105]）。\n\n接下来的 #cf_span[n] 行每行包含一个点的坐标。第 #cf_span[i] 行包含两个整数 #cf_span[xi] 和 #cf_span[yi]（#cf_span[|xi|, |yi| ≤ 109]，#cf_span[xi ≠ 0]）。没有两个点重合。\n\n如果存在这样的点，请输出 \"_Yes_\"，否则输出 \"_No_\"。\n\n你可以以任意大小写形式输出每个字母。\n\n在第一个例子中，可以移除第二个点。\n\n在第二个例子中，不存在满足条件的点。\n\n在第三个例子中，任意一个点都可以被移除。\n\n## Input\n\n第一行包含一个正整数 #cf_span[n]（#cf_span[2 ≤ n ≤ 105]）。接下来的 #cf_span[n] 行每行包含一个点的坐标。第 #cf_span[i] 行包含两个整数 #cf_span[xi] 和 #cf_span[yi]（#cf_span[|xi|, |yi| ≤ 109]，#cf_span[xi ≠ 0]）。没有两个点重合。\n\n## Output\n\n如果存在这样的点，请输出 \"_Yes_\"，否则输出 \"_No_\"。你可以以任意大小写形式输出每个字母。\n\n[samples]\n\n## Note\n\n在第一个例子中，可以移除第二个点。在第二个例子中，不存在满足条件的点。在第三个例子中，任意一个点都可以被移除。","is_translate":true,"language":"Chinese"},{"statement_type":"Markdown","content":"**Definitions**  \nLet $ n \\in \\mathbb{Z} $, $ 2 \\leq n \\leq 10^5 $, be the number of points.  \nLet $ P = \\{ (x_i, y_i) \\mid i \\in \\{1, \\dots, n\\} \\} $ be a set of distinct points in $ \\mathbb{R}^2 $, with $ x_i \\neq 0 $ for all $ i $.\n\n**Constraints**  \nFor all $ i \\in \\{1, \\dots, n\\} $:  \n- $ |x_i|, |y_i| \\leq 10^9 $  \n- $ x_i \\neq 0 $  \n- All points are distinct.\n\n**Objective**  \nDetermine whether there exists a point $ p \\in P $ such that all points in $ P \\setminus \\{p\\} $ lie on the same side of the $ OY $-axis (i.e., all have $ x > 0 $ or all have $ x < 0 $).  \n\nOutput \"Yes\" if such a point exists, \"No\" otherwise.","is_translate":false,"language":"Formal"}],"meta":{"iden":"CF900A","tags":["geometry","implementation"],"sample_group":[["3\n1 1\n-1 -1\n2 -1","Yes"],["4\n1 1\n2 2\n-1 1\n-2 2","No"],["3\n1 2\n2 1\n4 60","Yes"]],"created_at":"2026-03-03 11:00:39"}}