I don't know if this is my mistake or not. These two submissions differs only in 9th line (double changed to long double) but one submission is AC, while other gives RTE 1:
https://acm.timus.ru/getsubmit.aspx/10678502.cpp - AC
https://acm.timus.ru/getsubmit.aspx/10678503.cpp - RTE 1

It seems to me that this isn't normal.