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Hello, while solving this problem I noticed that the quotient of N and the number of relatively prime triples is almost 2 * PI (6.2831853071...). For example for N = 1000000 it's 1000000 / 159139 = 6.28381477, for N = 10000000 it's 10000000 / 1591579 = 6.28306857. So I would like to ask if it's true...

Hello,

what's the right answer when all vertices are lying in a line?

For example if the input is 1 1 2 1 3 1, what's the right output? Is it 0 or 3?

Thanks,
Pavel