Problems
Snake
Snake
Deduce the square, consisting of NxN cells filled with numbers from 1 to N^2 "snake" (see examples).
Input data
The first line is a single number N (2 ≤ N ≤ 100).
Output data
Output N rows of N numbers, separated by a space. Not be permitted beginning snake in the other corner or another of its direction.
Examples
Input example #1
3
Output example #1
1 2 6 3 5 7 4 8 9