Statement

Edoardo is busy setting up the servers that will host the second OIS round. However, he notes that the servers have something odd. Edoardo immediately recognizes the reason: the disks are broken again! The server will host N contests in the next N days, each contest start from hour A_i to hour B_i of day i. Edoardo knows he will need T hours to repair the broken disks. During the repair the server has to be turned off, but Edoardo doesn't want to turn off the server during a contest, so he has to do it at night. Since this is quite urgent, help Edoardo by finding the first contest after which he can turn off the server and repair the disks.