Age Calculator

Chef's planet is called Javad. A year on Javad has $N$ months numbered $1$ through $N$. For each valid $i$, the $i$-th month has $a_i$ days numbered $1$ through $a_i$. On Javad, years that are divisible by $4$ are leap years - the last month of each leap year is one day longer (it has $a_N + 1$ days). You are given Chef's birth date and the current date. Find the age of Chef in days, i.e. t