You are given a positive integer, days, which represents the total number of days an employee is available for work, starting from day $1$. You are also given a 2D array, meetings, where each entry meetings[i] $= [start_i, end_i]$ indicates that a meeting is scheduled from day $start_i$ to day $end_i$ (both inclusive).

Your task is to count the days when the employee is available for work but has no scheduled meetings.

Note: The meetings may overlap.

Constraints:

• $1 \leq$ days $\leq 100000$

• $1 \leq$ meetings.length $\leq 1000$

• meetings[i].length $==2$

• $1 \leq$ meetings[i][0] $\leq$ meetings[i][1] $\leq$ days