Hello, I have this minor problem in my Inputbox,

here's my code

Code:
Dim price As Double
price = 40

Dim qty As Integer
If chkIcedTea = vbChecked Then
    lstItem.AddItem chkIcedTea.Caption
    qty = InputBox("Enter Quantity:", "Input Quantity")
        
    lstQty.AddItem qty
    Call multiplier(price, qty)
    lstPrice.AddItem sum
   
End If

the error is "type mismatch" everytime I click the cancel and when the inputbox in empty. How can I avoid this error?