Manthan, Codefest 19 (open for everyone, rated, Div. 1 + Div. 2)
G
Polygons
Codeforces
2800
原题
← FH →
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You are given two integers $n$ and $k$.

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You need to construct $k$ regular polygons having same circumcircle, with distinct number of sides $l$ between $3$ and $n$.

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image Illustration for the first example.

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You can rotate them to minimize the total number of distinct points on the circle. Find the minimum number of such points.

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Input

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The only line of input contains two integers $n$ and $k$ ($3 \le n \le 10^{6}$, $1 \le k \le n-2$), the maximum number of sides of a polygon and the number of polygons to construct, respectively.

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Output

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Print a single integer — the minimum number of points required for $k$ polygons.

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Note

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In the first example, we have $n = 6$ and $k = 2$. So, we have $4$ polygons with number of sides $3$, $4$, $5$ and $6$ to choose from and if we choose the triangle and the hexagon, then we can arrange them as shown in the picture in the statement.

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Hence, the minimum number of points required on the circle is $6$, which is also the minimum overall possible sets.

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样例

Input #1
6 2
Output #1
6
InputCopy OutputCopy
Input #2
200 50
Output #2
708
InputCopy OutputCopy
题目信息
题号
1208G
时间限制
1 s
内存限制
256 MB
标签
贪心
数学
数论

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