Given a polynomial function \(f(x)=x^n\), the derivative of \(f(x)\) is defined by: 
\(f(x)=x^n \rightarrow f(x)^\prime=n.x^{n-1}\)

Here is an example:
\(f(x) = 4x^3 + 3x^2\\ f(x)’ = 12x^2 + 6x\)

Note that the derivative of a constant is \(0\). Now write a program that calculates the derivative of a polynomial function.

There will be several test cases. Each test case starts with an integer \(T\), indicating the number of terms the polynomial has. The next line describes the polynomial itself, formed by \(T\) terms, each separated by a \(\mathrm{plus}\) or \(\mathrm{minus}\) symbol. The plus/minus symbols will be surrounded by whitespace. Each of the terms will be in the form \(CxE\), where \(C\) and \(E \) represent the coefficients and the exponents, respectively. Note that, the exponent will be omitted if E=1. The variable \(x\) will be omitted if E=0. 

\(1 \le T \le100\\ 2 \le C \le 100\\ 2 \le E \le 100\)

For each test case, print the derivative of the given polynomial.

Input copy	Output copy
2 7x3 + 3x2 3 3x4 + 4x3 + 2x2 2 7x3 + 53	21x2 + 6x 12x3 + 12x2 + 4x 21x2