A company uses an employee ID code consisting of one letter from the Roman Alphabet $($A$-$Z$)$ followed by three decimal digits $(0-9).$ Calculate the total number of unique employee IDs possible with this system. A company uses an employee ID code consisting of one letter from the Roman Alphabet $($A$-$Z$)$ followed by three decimal digits $(0-9).$ Calculate the total number of unique employee IDs possible with this system.