The expression you provided includes a mix of numerical digits and letters (like "r" and "e"), which suggests that it might be representing a more complex mathematical expression or is formatted in a specific way. However, as it stands, it's not a standard numerical expression that can be directly computed.
If you clarify what "r" and "e" represent in this context, or if they are to be excluded or replaced with numbers, I can assist you further in calculating or simplifying the expression.