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Problems

Board Blitz

Board Blitz

Time limit 2.5 seconds
Memory limit 64 MiB

In this problem, you have to quickly find the final position in a game on a square board.

Consider a game on a square checkered board divided into 8×8 square cells. Initially, the board is empty. Two players take turns one after another. The first player controls white pieces, the second player controls black pieces. A turn consists in either a movement or a jump of the player’s pieces.

To make a movement, a player chooses one of the four directions and shifts all her pieces simultaneously by one cell in that direction. If a piece moves off the board, it disappears. Furthermore, for each of the eight border cells where no piece could have been shifted to during a movement in this direction, the player may place a new piece of her color in that cell. If a piece appears on a cell which contains a piece of opposite color, that piece (of opposite color) disappears from the board.

To make a jump, a player takes all her pieces and simultaneously transfers them to cells which correspond to a 90-degree rotation around the board center. The rotation must be clockwise for white pieces and couter-clockwise for black pieces. Same as after a movement, if a piece appears on a cell which contains a piece of opposite color, that piece (of opposite color) disappears from the board.

Both players agreed to make turns according to the values obtained from a random number generator: the first random number determines the first player’s turn, the second number gives the second player’s turn, the third number specifies the next turn of the first player, and so on.

You are given the parameters a, c and s of a linear congruential pseudorandom number generator in a 64-bit signed integer data type. This generator works in the following way: to get the next random number, the assignment s_new := s_olda + c is carried out, the result is truncated to a 64-bit signed integer data type, stored as the new value of s and returned as the next random number.

A turn is determined by the number p obtained as the highest 11 bits of the random number (in other words, p is the result of an integer division of s by 2^53 rounded towards zero). If p < 0, the turn will be a jump. Otherwise, the turn will be a movement, bits 8 (multiplied by 1) and 9 (multiplied by 2) form the number of direction (0 is up, 1 is left, 2 is down, 3 is right), and bits 0 through 7 specify which of the eight cells will contain new pieces. The cells are numbered 0 through 7 from top to bottom or from left to right (depending on the direction).

Given numbers a, c and s, and also the number of half-turns n, find the final position on the board. A half-turn is a turn by one of the two players. It is guaranteed that n is even. Additionally, it is guaranteed that in all the judges’ tests except the example, the triple of numbers a, c and s is chosen uniformly at random from all such triples that the linear congruential generator specified by them has a period of exactly 2^64.

Input data

The first line contains an integer n, the number of half-turns in the game, and also integers a, c and s which are the parameters of the random number generator (2n30 000 000, n is even, -2^63a, c, s < 2^63, the period of the generator is exactly 2^64).

Output data

Print eight lines with eight characters on each line: the state of the board after all turns have been completed. Denote empty cells with character “.”, white pieces with character “W” and black pieces with character “B”.

Examples

Input example #1
10 12345678901234565 23456789012345679 12345678
Output example #1
.BB.....
......BB
........
WW......
WW......
W......B
W.......
.W......

Note

The following table shows the sequence of values of s, values of p and specific bits of p in the example.

The pictures below show all the intermediate states of the board in the example.

Source 2014 Petrozavodsk, Ivan Kazmenko Contest, August 22, Problem B