//step 2
        //create chessboard

        var chessBoard = [String: String]()

        let letters = "abcdefgh"

        for (index, character) in letters.characters.enumerated() {

            let temporaryIndex = index + 1

            if temporaryIndex % 2 == 1 {

                for indexString in 1...8 {

                    if indexString % 2 == 1 {

                        chessBoard[String.init(format: "%@%d", String.init(character), indexString)] = "black"
                    } else {

                        chessBoard[String.init(format: "%@%d", String.init(character), indexString)] = "white"
                    }
                }
            } else {

                for indexString in 1...8 {

                    if indexString % 2 == 1 {

                        chessBoard[String.init(format: "%@%d", String.init(character), indexString)] = "white"
                    } else {

                        chessBoard[String.init(format: "%@%d", String.init(character), indexString)] = "black"
                    }
                }
            }
        }

        func squareByCoordinate(letterSquare letter: String, numberSquare number: Int, inChessboard chessboard: [String: String]) -> (String) {

            return "square at coordinate \(letter)\(number) have \(chessboard[letter + String(number)]!) color"
        }

        print(chessBoard)
        print(squareByCoordinate(letterSquare: "f", numberSquare: 7, inChessboard: chessBoard))