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):

    if n == 1:
        result = 1
    elif n == 2:
        result = 2
    else:
        result = n + 2 ** (n-2)

    print(result)

    for i in range(n):
        s = ''
        if i % 2 == 0:
            for j in range(n):
                if j % 2 == 0:
                    s += 'C'
                else:
                    s += '.'
        else:
            for j in range(n):
                if j % 2 == 0:
                    s += '.'
                else:
                    s += 'C'
        print(s)


if __name__ == "__main__":
    n = int(input())
    solve(n)
