Battleship game

from random import randint
def battleship():
    board = []
    size = int(raw_input("Tell me the size of the field:"))
    turns = int(raw_input("Tell me the turns you will use:"))
    print

    for x in range(size):
        board.append(["O"] * size)

    def print_board(board):
        for row in board:
            print " ".join(row)

    print "Let's play Battleship!"
    print_board(board)
    print

    def random_row(board):
        return randint(0, len(board) - 1)

    def random_col(board):
        return randint(0, len(board[0]) - 1)

    ship_row = random_row(board)
    ship_col = random_col(board)

    for turn in range(turns):
        guess_row = int(raw_input("Guess Row:"))-1
        guess_col = int(raw_input("Guess Column:"))-1
        print
        if guess_row == ship_row and guess_col == ship_col:
            print "Congratulations! You sunk my battleship!"
            break
        else:
            if ( 0 > guess_row > len(board) - 1) or (0 > guess_col > len(board[0]) - 1):
                print "Oops, that's not even in the ocean."
            elif (board[guess_row][guess_col] == "X"):
                print "You guessed that one already."
            else:
                print "You missed my battleship!"
                board[guess_row][guess_col] = "X"
            print "Turns taken: %i; Turns left: %i" % (turn + 1, turns - turn - 1)
            print_board(board)
            print
        if turn == turns - 1:
            print "Game Over"

battleship()