{"problem":{"name":"Gentle Pairs","description":{"content":"On the $xy$\\-plane, We have $N$ points numbered $1$ to $N$. Point $i$ is at $(x_i, y_i)$, and the $x$\\-coordinates of the $N$ points are pairwise different. Find the number of pairs of integers $(i, j","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc187_b"},"statements":[{"statement_type":"Markdown","content":"On the $xy$\\-plane, We have $N$ points numbered $1$ to $N$. Point $i$ is at $(x_i, y_i)$, and the $x$\\-coordinates of the $N$ points are pairwise different.\nFind the number of pairs of integers $(i, j)\\ (i < j)$ that satisfy the following condition:\n\n*   The line passing through Point $i$ and Point $j$ has a slope between $-1$ and $1$ (inclusive).\n\n## Constraints\n\n*   All values in input are integers.\n*   $1 \\le N \\le 10^3$\n*   $|x_i|, |y_i| \\le 10^3$\n*   $x_i \\neq x_j$ for $i \\neq j$.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$x_1$ $y_1$\n$\\vdots$\n$x_N$ $y_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc187_b","tags":[],"sample_group":[["3\n0 0\n1 2\n2 1","2\n\nThe slopes of the lines passing through $(0, 0)$ and $(1, 2)$, passing through $(0, 0)$ and $(2, 1)$, and passing through $(1, 2)$ and $(2, 1)$ are $2$, $\\frac{1}{2}$, and $-1$, respectively."],["1\n-691 273","0"],["10\n-31 -35\n8 -36\n22 64\n5 73\n-14 8\n18 -58\n-41 -85\n1 -88\n-21 -85\n-11 82","11"]],"created_at":"2026-03-03 11:01:14"}}