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):
    m = [['.']*(n+2) for _ in range(n+2)]
    c = 0
    for i in range(1, n+1):
        for j in range(1, n+1):
            if m[i+1][j] == '.' and \
               m[i-1][j] == '.' and \
               m[i][j-1] == '.' and \
               m[i][j+1] == '.':
                m[i][j] = "C"
                c += 1
    print(c)
    for i in range(1, n+1):
        print(''.join(m[i][1:-1]))


def main():
    n = int(input())
    solve(n)


main()
