function solve(title, age) {

    age = +age;

    switch (true) {
        case title === "m" && age >= 16:
            console.log("Mr.")
            break;
        case title === "m" && age < 16:
            console.log("Master")
            break;
        case title === "f" && age >= 16:
            console.log("Ms.")
            break;
        case title === "f" && age < 16:
            console.log("Miss")
            break;
        default:
            break;
    }
}

solve("f", "17");