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 main():
    n = int(input())
    sol = [["C" for _ in range(n)] for _ in range(n)]

    for i in range(n):
        for j in range(n):
            if sol[i][j] == "C":
                if j > 0 and sol[i][j - 1] == "C":
                    sol[i][j - 1] = "."

                if j < n - 1 and sol[i][j + 1] == "C":
                    sol[i][j + 1] = "."

                if i > 0 and sol[i - 1][j] == "C":
                    sol[i - 1][j] = "."

                if i < n - 1 and sol[i + 1][j] == "C":
                    sol[i + 1][j] = "."

    count = 0
    for i in range(n):
        for j in range(n):
            if sol[i][j] == "C":
                count += 1

    print(count)
    for i in range(n):
        for j in range(n):
            print(sol[i][j], end=' ')
        print()


if __name__ == "__main__":
    main()
