Hello Codeforces!↵
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I am a participant for ICPC 2019 in PSP region. There is a rule (I am very surprised because it is still draft even some regional ended) for WF teams Selection in [here](http://blog.sina.com.cn/s/blog_b946da100102zsjx.html)↵
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. The blog mentions the Shieh-Ishihata formula, but I couldn't find it anywhere. Does anyone have information about that formula?
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I am a participant for ICPC 2019 in PSP region. There is a rule (I am very surprised because it is still draft even some regional ended) for WF teams Selection in [here](http://blog.sina.com.cn/s/blog_b946da100102zsjx.html)
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