\(7^{th}\) round, March \(5^{th}\) 2016
Mirko has been a very good boy, so he got exactly what he wanted for his birthday, a "Young physicist"
kit! In the kit, there are \(N\) types of resistors, connecting wires and an ohmmeter. If a resistor is of
type \(i\), it provides a resistance of precisely \(R@@RISE_MATH_BLOCK_0@@2-R\)3-...-RK)
and the following formula holds:
\(R_{ekv} = R@@RISE_MATH_BLOCK_1@@2 + R\)3 + ... + \(R_{K}\)
When the circuit is parallel, it is written in the following way:
(R1|R2|R3|...|RK)
and the following formula holds:
\(R_{ekv}\) =
1
1
^{R}1 ^{+} ^{1}
^{R}2 ^{+} ^{1}
{R} ^{+}}^{+
1
\(RK\)
Mirko was excited to bring his new toy to school, where he showed it to all his friends. Unfortunately
for him, the teacher also noticed the toy. She quickly connected a circuit and is now asking Mirko to
tell her the equivalent resistance of the circuit. Help Mirko and answer the teacher’s question!

In test cases worth 20% of total points, it will hold:
• \(N = 3\)
• S is going to consist of exactly three resistors, \(R\)1, \(R\)2 and \(R\)3, not necessarily in that order
In test cases worth 40% of total points, S is going to have exactly one pair of brackets.

The first line of input contains the integer \(N\) (1 ⩽\(N\) ⩽9) from the task.
The following line contains \(N\) real numbers \(R_{i}\) (\(0 < R_{i} < 100\)) from the task.
The last line contains the circuit S, that will not be longer than 100 000 characters. S will only consist
of the following characters: ’R’, ’1’ – ’9’, ’(’, ’)’, ’-’ and ’|’. The number of pairs of brackets will be
minimal, and the brackets will be paired properly. Inside of a pair of brackets, there will not be the
character ’-’ and the character ’|’ at the same time. The circuit will only consist of the resistors from
the kit and it is possible that not all types of resistors are used, or that one type of resistor is used
several times.

The first and only line of output must contain the number from the task. A deviation from the official
solution of ±0.00001 is tolerated.

생성자가 기록되지 않았습니다.

출처 COCI 2015/2016 Contest 7