Formula
문제
Nick is a mathematician and his speciality is Boolean logic, especially repetition-free functions. The Boolean function is repetition-free if it can be represented as a repetition-free formula. Formula is repetition-free if each variable occurs in the formula only once.
Let us fix the syntax of considered logical formulae:
- Variables — letters from ‘
a’ to ‘k’; - Parentheses — if E is a formula, then (E) is another;
- Negation — ¬E is a formula for any formula E;
- Conjunction — E1 ∧ E2 ∧ · · · ∧ En.
- Disjunction — E1 ∨ E2 ∨ · · · ∨ En.
The operations are listed from the highest priority to the lowest.
The problem is to represent given Boolean function by a repetition-free formula.
입력
The only line of input contains the Boolean function represented as a string consisting of characters ‘a’..‘k’, ‘(’, ‘)’, ‘ ’, ‘&’ and ‘|’. The last three tokens stand for ¬, ∧ and ∨ respectively. Tokens can be separated by an arbitrary number of spaces. The line contains 1 000 characters at most. The formula in the file is syntactically correct.
출력
The first line of the output file must contain “Yes” if function is repetition-free and “No” otherwise.
In the former case the following line must contain the repetition-free formula for given Boolean function in the same format as in the input file. The line must contain no more than 1 000 characters.
예제
예제 1
(a | b) & (a | c)
Yes a | b & c
예제 2
d&~d
No
예제 3
d & ~d | ~((a|~b) & (a|c))
Yes ~a&(b|~c)
예제 4
a & b | ~ a & ~b
No