# 103. Triangular Matrix Solver

## I'm a slow walker, but I never walk backwards.

Write a program to solve a system of equations. In particular we are given an $n$ by $n$ upper triangular matrix $A$ and a $n$ by $1$ vector $y$, and we would like to find another $n$ by $1$ vector $x$ so that $Ax = y$. Since $A$ is upper triangular, i.e., all the elements below the diagonal are zero, we can use a simple procedure called backward substitution to get the vector $x$. Since $A_{n,n} \times x_n=y_n$, so we conclude that $x_n = y_n / A_{n,n}$. Since we know $x_n$ now, we can easily compute $x_{n-1}$, then $x_{n-2}$, and so on, until we finally compute $x_1$.

## Input

The first line of the input has the number of rows and columns $n$. $n$ is between 1 and 16. Each of the following $n$ lines has $n$ double numbers in $A$. Each of the following $n$ lines has the numbers in $y$. Note that all elements of matrix and vector are double numbers.

## Output

The output has $n$ lines. Each line is a number in $x$. You should output the double numbers in %f\n format.

## Sample input

31.0 2.0 3.00.0 2.0 1.00.0 0.0 4.02.03.0-4.0

## Sample output

1.0000002.000000-1.000000