Field Calculater

Dear tech Support Team,
I am working on table i want some correction in script for calculating field
I have Data in Grid_code field in the form of 1 to 6
In grid_code field there is value 1 to 6 i want 1 is convert as Very low, 2 Is Low, 3 is Moderate, 4 is High and 5 is Very high in Class field i am using following script

Dim Output as String
If [Class] = 1 Then
Output = "Very Low"
Elseif [Class] = 2 Then
Output = "Low"
Elseif [Class] = 3 Then
Output = "Moderate"
Elseif [Class] = 4 Then
Output = "High"
Elseif [Class] = 5 Then
Output = "Very High"
Elseif [Class] = 6 Then
Output = "Extreme"
Else
Output = "xxx"
end if
Please help me to correct this script or please tell me where i get solution


Thanks & Regards
Abhishek Misra