PROGRAMMING:Infix expression to suffix expression

Infix expression means that the operator is in the middle of the operands (for example: 3 * (4 + 2)). Infix expression is a commonly used arithmetic expression, but it is not easy to be parsed by computer, because it is necessary to consider not only the priority of operator, but also the treatment of bracket. But infix expression is still used in many programming languages, because it conforms to people's common usage. Suffix expression means that it does not contain brackets, operators are placed after two operands, and all calculations are carried out strictly from left to right according to the order in which operators appear (the priority rules of operators and brackets are not considered).
Given an infix expression, please convert it to a suffix expression and output it.
###Input format:
There is only one line, which is a string no more than 1000 in length, representing an infix expression. The expression contains only + - * / and parentheses. Parentheses can be nested. Operators and operands are separated by a space. The data ensures that the negative number will not appear in the input operands and the divisor will not be 0.
###Output format:
Output the corresponding suffix expression. Operators and operands are separated by a space, but there is no extra space at the end of the line.
###Input example:
```in
3 * ( 4 + 2 )
```
###Output example:
```out
3 4 2 + *
```







answer：If there is no answer, please comment