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Límite de tiempo: 5 s Límite de memoria: 256 MB Puntuación total: 100

#6578. 三角形

Estadísticas

在平面上给定 $n$ 个点。我们感兴趣的是顶点都在这些给定点中,且面积在区间 $[A, B]$ 内的直角三角形的数量。

输入格式

第一行包含三个整数 $n, A, B$ ($1 \le n \le 2000$, $1 \le A \le B \le 10^{18}$)。 接下来的 $n$ 行描述了各个点。第 $i$ 行包含两个整数 $x_i, y_i$ ($-10^9 \le x_i, y_i \le 10^9$),表示第 $i$ 个点的坐标。输入中的点互不相同。

输出格式

输出一行,包含顶点在给定点中且面积在区间 $[A, B]$ 内的直角三角形的数量。

样例

输入格式 1

7 5 25
0 0
2 0
0 2
10 0
0 10
3 3
3 -3

输出格式 1

3

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