说明

Many students of LingNan Normal University are living in Yanling Campus, which is 4.5 kilometers from the main campus – Leiyan. Students in Yanling have to either take a bus or ride a bike to go to school. Due to the bad traffic in ZhanJian, many students choose to ride a bike.
We may assume that all the students except "Charley" ride from Yanling to Leiyan 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 Yanling, he will look for someone who is setting off to Leiyan. If he finds someone, he will follow that rider, or if not, he will wait for someone to follow. On the way from Yanling to Leiyan, 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 Yanling is zero. Given the set off time and speed of the other students, your task is to give the time when Charley arrives at Leiyan.

输入格式

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.

输出格式

Output one line for each case: the arrival time of Charley. Round up (ceiling) the value when dealing with a fraction.

4
20	0
25	-155
27	190
30	240
2
21	0
22	34
0

780
771

提示

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