General Caster Nested if Formula generating error: Unexpected ')'

Hello, my General Caster formula is trying to check the duration value is not null before it completes the logic decision to change a status column but I get this error:

General Caster Formula Error: Unexpected ‘)’

The Formula:

IF({item’s duration} <>“0”,
IF({item’s duration} <25, first_value “Took Call”, second_value “Missed Call”), “”)

It might be a simple solution but I am still fairly new at this so some help would be much appreciated.