Bypass matrix with "snake"#488

Bypass matrix with "snake"

1 second

128 megabytes

Very easy

For a given number $n$ , fill the square matrix of size $n \times n$ n \times n with integers from $1$ to $n^{2}$ n^2 as follows:

The number $1$ is in the upper left corner;
Then numbers go like a snake, i.e., in ascending order from left to right in the odd lines and from right to left in the even lines.

Input

One integer $n$ ( $1 \leq n \leq 100$ 1 \leq n \leq 100).

Print the filled matrix in the form of $n$ rows by $n$ integers each.

Example 1

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n \times n

n^{2}

1 \leq n \leq 100