PROGRAMMING:Derivation of one variable polynomial function (enhanced version)
In this paper, a polynomial function of one variable (such as $$f (x) = ax ^ B + CX ^ D +... $) is given, and its derivative function is obtained. The results are output in standard writing format, and the similar items must be merged and arranged in descending order. If the result polynomial is null, only 0 is output.
The absolute value of each coefficient is less than 100, and the exponent is a non negative integer less than 100. The length of the input string does not exceed 3000. Variables are represented by the letter $$x $. The topic guarantees that the input polynomials are * legal * *.
###Input format:
Enter a polynomial string on one line.
###Output format:
Output the string in a standard writing format on one line.
###Input example:
```in
x^4-3x^2+4
```
###Output example:
```out
4x^3-6x
```
answer：If there is no answer, please comment
The absolute value of each coefficient is less than 100, and the exponent is a non negative integer less than 100. The length of the input string does not exceed 3000. Variables are represented by the letter $$x $. The topic guarantees that the input polynomials are * legal * *.
###Input format:
Enter a polynomial string on one line.
###Output format:
Output the string in a standard writing format on one line.
###Input example:
```in
x^4-3x^2+4
```
###Output example:
```out
4x^3-6x
```
answer：If there is no answer, please comment