' fb 1.05.0 Win64

Dim As Integer a, b
Do
  Print "Enter two integers separated by a space : ";
  Input "", a, b
  If Abs(a) > 1000 OrElse Abs(b) > 1000 then
    Print "Both numbers must be in the interval [-1000, 1000] - try again"
    Print
  Else
    Print "Their sum is"; a + b
    Exit Do
  End If
Loop
Print
Print "Press any key to quit the program"
Sleep