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## 1401. Gamers

Time limit: 2.0 second
Memory limit: 64 MB
Mr. Chichikov is a wealthy man. Besides other ways of earning the money he used this one: he argued with some blunderers that he would be able to prove that it is impossible to pave the 512 × 512 square checker-board with the figures:
 X XX X XX XX X XX X
and he always won. Once one of those blunderers happened to be not so silly and he claimed that he was able to pave the 512 × 512 square checker-board without the upper right cell with those figures. Chichikov blurted out that he could pave any 2n × 2n square checker-board without one arbitrary cell with those figures. One word led to another and they bet. Chchikov felt that he wouldn’t prove his case. Help him!

### Input

The first input line contains an integer n (1 ≤ n ≤ 9). The second line consists of two integers x and y — those are the coordinates of the deleted cell (1 ≤ x, y ≤ 2n). x is a number of a row and y is a number of a column. The coordinates of the upper left cell of the board are (1, 1).

### Output

Your program is to output 2n lines with 2n numbers in each line. There must be 0 on the place of the deleted cell. On the other places there must be numbers from 1 to (22n − 1) / 3 — a number of figure that covers this cell. It is clear that equal numbers must form a figure. If such a coverage is impossible, output “−1”.

### Sample

inputoutput
2
1 1
0 1 3 3
1 1 4 3
2 4 4 5
2 2 5 5
Problem Author: Alex Samsonov
Problem Source: The 12th High School Pupils Collegiate Programming Contest of the Sverdlovsk Region (October 15, 2005)
Tags: none