Hi,

I tried to solve problem G from the 65th educational round: http://mirror.codeforces.com/contest/1167/problem/G

However, I get WA on test 1 because the difference between my answer and the expected one is 10^-7, instead of 10^-9: http://mirror.codeforces.com/contest/1167/submission/54524130

On my PC (ubuntu) the answer I get is 1.570796326796 with an error of -4.0001336*10^-12, which should pass the test.

What causes the difference and how can I solve it?

Thanks!