Unable to get output from VbScript ,using Invoke Vb Script activity, into UiPath Variable

Unable to get output from VbScript ,using Invoke Vb Script activity, into UiPath Variable. Nothing is returned from the script in output variable of the "Invoke Vb Script activity".

In order to get the value from VB script into the variable defined in the "Result" property of the Invoke Vb Script activity, please add below line of code at the end of the script:

Wscript.Echo Sum

Here "Sum" is the variable whose value needs to be returned from the VB script to the UiPath activity.Below is the sample script:

"'Setting the arguments to fetch them from the command line
Set args = Wscript.Arguments
For each arg in args
a = args(0)
b = args(1)
Next

'Function to get the input value
Function Sum(a,b)
c=Cint(a)+Cint(b)
c=CStr(c)

Sum= c

Wscript.Echo Sum

End Function


Call Sum(a,b)"