Function PROBKS(ALAM)
    EPS1 = 0.001
    EPS2 = 0.00000001
    A2 = -2# * ALAM ^ 2
    FAC = 2#
    PROBKS = 0#
    TERMBF = 0#
    For J = 1 To 100
        TERM = FAC * Exp(A2 * J ^ 2)
        PROBKS = PROBKS + TERM
        AAA = Abs(TERM)
        If AAA < EPS1 * TERMBF Or AAA < EPS2 * PROBKS Then
            Exit Function
        End If
        FAC = -FAC
        TERMBF = Abs(TERM)
    Next J
    PROBKS = 1#
End Function