protocol Ingredient {

    var ingredient: String { get set }

    init()
}

struct Espresso: Ingredient {

    var ingredient: String

    init() {

        ingredient = "☕️"
    }
}

struct Milk: Ingredient {

    var ingredient: String

    init() {

        ingredient = "🥛"
    }
}

struct Soy: Ingredient {

    var ingredient: String

    init() {

        ingredient = "🌱"
    }
}