A8275 | New Year Snowflake

The first line contains two integers $n$ and $k$ ( $1<=n<=200000$ , $0<=k<=10$ ) — the number of the surviving snowflake crystals and the maximum number of melted crystals, correspondingly. Next $n$ lines contain the coordinates of the crystals that are left in the following form: " $x_{i}$ $y_{i}$ ". The coordinates are integers and do not exceed $5·10^{8}$ in absolute value. All given points are different.

The first line contains an integer $c$ — the number of possible symmetry centers. Next $c$ lines should contain the centers' descriptions. Each symmetry center is described by a couple of coordinates " $x$ $y$ ", separated by a space. Print the coordinates with absolute error not exceeding $10^{-6}$ . You are allowed to print the symmetry centers in any order. All printed points should be different. If there exist an infinite number of possible symmetry centers, print the single number "-1".

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