Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
Home Page
F.A.Qs
Statistical Charts
Problems
Submit Problem
Online Status
Prob.ID:
Register
Update your info
Authors ranklist
Current Contest
Past Contests
Scheduled Contests
Award Contest
User ID:
Password:
  Register
Language:
Turning in Homework
Time Limit: 1000MSMemory Limit: 30000K
Total Submissions: 1233Accepted: 540

Description

Bessie must turn in her homework for her C classes (1 <= C <= 1,000) at Moo U so that she still has time to chew the cud with her fellow classmates as they wait for the bus to go home.

Teachers accept homework submissions only after they have finished their classes and also cleaned the chalkboard, put away lab supplies,and so on. The input data tells the earliest time a teacher will accept homework.

Bessie starts at one end (distance 0) of a hallway H (1 <= H <= 1,000) meters long and walks at the rate of one meter per second to various classrooms (in any order she chooses) to turn in her homework. Each classroom is located along this hallway, as well as the door to the waiting area for the buses.

Given the location of both the exit and the classrooms and also the teachers' schedules, determine the earliest time that Bessie can exit the door to the waiting area for the buses. Bessie must turn in all her homework before exiting. The act of turning in the homework takes no time, by the way.

Input

* Line 1: Three integers: C, H, and B. B (0 <= B <= H) is the distance from the hall entrance to the bus waiting area.

* Lines 2..C+1: Each line contains two integers that describe a classroom where homework is to be submitted. The first integer (0..H) is the number of meters to the classroom from the hallway entrance. The second integer (0..10,000) is the first time (in seconds) that the teacher for that course will accept homework.

Output

* Line 1: A single integer: the earliest second that Bessie can exit the door to the waiting area for the buses.

Sample Input

4 10 3
8 9
4 21
3 16
8 12

Sample Output

22

Hint

Time   Action

0 Bessie walks to the classrooms 8 meters down the hall (at 8m)
8 Bessie waits 1 second
9 Bessie turns in the first set of homework
9 Bessie waits 3 seconds, thinking about cool hay in the summertime
12 Bessie turns in the other homework for this location
12 Bessie walks back to the classroom 4 meters down the hall (at 4m)
16 Bessie waits 5 seconds, thinking of a handsome bull she once met
21 Bessie turns in her homework
21 Bessie walks back to the classroom 1 meters down the hall (at 3m)
22 Bessie turns in her homework
22 Bessie exits, since this also the location of the bus exit

Thus, Bessie can leave at time 22. No better schedule exists.

Source

[Submit]   [Go Back]   [Status]   [Discuss]

Home Page   Go Back  To top


All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator