You are in charge of all of a certain country's radio broadcasts. At time 0, you send outgoing radio waves to 
~N~ (
~1 \le N \le 1\,000~) receivers, and whenever a wave meets a receiver, the receiver immediately sends the wave back to you. If the waves travel at the same speed, which incoming radio waves will arrive between time 
~S~ and time 
~T~ (
~1 \le S \le T \le 10\,000~), inclusive?
Input Specification
On one line, ~N~, ~S~ and ~T~, separated by single spaces followed by ~N~ separate lines, each representing the time a radio wave meets a receiver. The times will be positive integers no greater than 
~10\,000~.
Output Specification
The number of radio waves that made it back between time ~S~ and time ~T~.
Sample Input
3 2 4
1
2
4
Sample Output
2
Explanation
Only the first two radio waves make it back, at times of exactly 2 and 4.
Comments
The problem should mention round trip time imo...