I am having problems with calling the function in Swift, when building an iOS app.

```
@IBOutlet weak var vyseHypoteky: UITextField!
@IBOutlet weak var dobaSplaceni: UITextField!
@IBOutlet weak var urokovaSazba: UITextField!
@IBOutlet weak var mesicniSplatka: UITextField!

@IBAction func zmenaVyseHypoteky(sender: UISlider) {
    var currentValue = Int(sender.value)
    vyseHypoteky.text = "\(currentValue)"
    vypoctiSplatku()
}

@IBAction func zmenaDobySplaceni(sender: UISlider) {
    var currentValue = Int(sender.value)
    dobaSplaceni.text = "\(currentValue)"
}

@IBAction func zmenaUrokoveSazby(sender: UISlider) {
    var currentValue = Int(sender.value)
    urokovaSazba.text = "\(currentValue)"
}

func vypoctiSplatku () {
    let HU:Int? = vyseHypoteky.text.toInt()
    let ipa:Int? = urokovaSazba.text.toInt()
    let n:Int? = dobaSplaceni.text.toInt()

    var ipm = ipa! / 12

    var zavorka = 1+ipm
    var vypoctenaZavorka = mocnina(mocnenec: zavorka, mocnitel: n)

    var citatel = HU! * ipm * vypoctenaZavorka
    var jmenovatel = vypoctenaZavorka - 1

    var splatka = citatel / jmenovatel

    mesicniSplatka.text = ("\splatka")
    }

func mocnina (mocnenec: Int, mocnitel: Int) -> Int {
    var mocnina = 1
    for _ in 1...mocnitel {
        mocnina *= mocnenec
    }
    return mocnina
    }

```

The app is calculating a number by my formula. I want to use my function to calculate the x^y, this the "mocnina" function where I want to use two int, the x is "mocnenec" and the y is "mocnitel".

And finally I want to send the final int from variable "splatka" to text inout filed "mesicniSplatka".

But I am getting errors in calling the function "mocnina" --> `var vypoctenaZavorka = mocnina(mocnenec: zavorka, mocnitel: n)`

`Extraneous argument label 'mocnenec:' in call
Value of optional type 'Int?' not unwrapped; did you mean to use '!' or '?'?`

and in the end with `mesicniSplatka.text = ("\splatka")`

`Invalid escape sequence in literal`

How to fix it? Thx for helping a total newbie :)