class Shape {
    var lineCount: Int

    init(lineCount: Int) {
        self.lineCount = lineCount
    }
}

class Square: Shape {
    var sideLength: Int

    init (sideLength: Int) {
        self.sideLength = sideLength
        super.init(lineCount: 4)
    }
}

let square = Square(sideLength: 5)
//square.lineCount is 4

print("lineCount is \(square.lineCount)")