#913. Postfix expression
You get a postfix (reverse Polish) expression separated by spaces (`+`, `-`, `*`). Find its value using a stack. Example: `3 4 + 2 *` = 14.
### Input
One line.
### Output
A number.
Examples
Input
4
Output
4
Input
1
Output
1
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.