A theater has n seats, indexed 1..n, all starting with 0 check-ins. Over the course of an event, m check-in scans occur; each scan l r marks one additional check-in for every seat in the inclusive range [l, r] (a seat may be marked by several different scans). After all m scans, given a threshold T, count how many seats ended up with a check-in count >= T.
Input format
Line 1: three integers n m T.
Next m lines: two integers l r each.
Output format
A single integer: the number of seats whose final check-in count is >= T.
Constraints
- 1 <= n <= 100000
- 0 <= m <= 100000
- 1 <= l <= r <= n
- 0 <= T <= 100000