Use a stack to convert prefix expressions directly to postfix expressions. You may not use recursion.

Write a program that accepts a prefix expression containing single letter operands and the operators +, -, *, /, and $ (representing exponentiation). Output the corresponding postfix expression.

For example, if your input is *AB, then output should be AB*. Output of BA* is considered incorrect.

You may not use library functions. In processing the input, you should expect to read line by line and within a line, character by character.