Iahub likes chess very much. He even invented a new chess piece named Coder. A Coder can move (and attack) one square horizontally or vertically. More precisely, if the Coder is located at position (*x*, *y*), he can move to (or attack) positions (*x* + 1, *y*), (*x*–1, *y*), (*x*, *y* + 1) and (*x*, *y*–1).

Iahub wants to know how many Coders can be placed on an *n* × *n* chessboard, so that no Coder attacks any other Coder.
The first line contains an integer *n* (1 ≤ *n* ≤ 1000).
def solve():
    n = int(input())
    mat = [['.' __ in range(n)] for _ in range(n)]
    total = 0
    
    for i in range(n):
        for j in range(n):
            if i & 1 and j & 1:
                mat[i][j] = 'C'
                total += 1
            elif not (i & 1) and not (j & 1):
                mat[i][j] = 'C'
                total += 1
                
    print(total)
    
    for m in mat:
        print(''.join(m))

    
if __name__ == "__main__":
    solve()
    