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Problem 1318
Ride to School
Time Limit: 1000ms
Memory Limit: 65536kb
Description
Many graduate students of USTC are living in West Campus, which is 4.5 kilometers from the East campus(Of course,actually it is not so far away ). Students in West Campus have to either take a bus or ride a bike to go to school. Many students choose to ride a bike. We may assume that all the students except "Charley" ride from West Campus to East Campus at a fixed speed. Charley is a student with a different riding habit – he always tries to follow another rider to avoid riding alone. When Charley gets to the gate of West Campus, he will look for someone who is setting off to East Campus. If he finds someone, he will follow that rider, or if not, he will wait for someone to follow. On the way from West Campus to East Campus, at any time if a faster student surpassed Charley, he will leave the rider he is following and speed up to follow the faster one. We assume the time that Charley gets to the gate of West Campus is zero. Given the set off time and speed of the other students, your task is to give the time when Charley arrives at East Campus.
Input
There are several test cases. The first line of each case is N (1 <= N <= 10000) representing the number of riders (excluding Charley). N = 0 ends the input. The following N lines are information of N different riders, in such format: Vi [TAB] Ti Vi is a positive integer <= 40, indicating the speed of the i-th rider (kph, kilometers per hour). Ti is the set off time of the i-th rider, which is an integer and counted in seconds. In any case it is assured that there always exists a nonnegative Ti.
Output
Output one line for each case: the arrival time of Charley. Round up (ceiling) the value when dealing with a fraction.
Sample Input
4
20	0
25	-155
27	190
30	240
2
21	0
22	34
0
Sample Output
780
771
University of Science and Technology of China
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