I have problem I used inputbox, How to loop the Xcor and Ycor inputbox untill the number of the input station

Code:
Dim stnNumber As Integer
Dim Xcor As Double
Dim Ycor As Double
stnNumber = Val(InputBox("Enter a number of station(zero to quit):", "Input station"))
Xcor = Val(InputBox("Enter a X coordinate (zero to quit): =", "Input X coordinate"))
Ycor = Val(InputBox("Enter a Y coordinate (zero to quit): =", "Input Y coordinate"))