Like every boy, Fedya has toy cars. However, he was more fortunate than an ordinary boy — all n of his cars are radio-controlled. All day long he can arrange various car races and play with friends.
Of all the types of racing, Fedya prefers straight-line racing. In this format of the competition, the track has a straight line and is endless (competitions go on until Feda gets tired of it). Initially, each of the n cars is at some distance from the start — has a head start of x
i meters. On command, all cars start their movement from the start, while each car moves during the race at a constant speed v
i meters per second. All cars move in the same direction — are removed from the start.
Feda was recently given a video camera and wants to capture the highlights of the race. First of all, Fedya wants to capture the first overtaking of the race, that is, the first moment in time when two cars are at the same distance from the start.
Since this event can be expected for a very long time, Fedya wants to set the camera to turn on automatically during overtaking. However, Fedya himself cannot find the time that will pass from the start of the race to the time of the first overtaking. Help Fedya — write a program that finds the desired value.
Input
The first line of the input file contains a single number n — number of cars on the track (2 ≤ n ≤ 100). Each of the next n lines contains two integers x
i and v
i — distance from the start (in meters) and speed of car i (in meters per second), respectively (1 ≤ x
i, v
i ≤ 1000).
Initially, no two cars are at the same point. It is guaranteed that at least one overtaking will occur during the race.
Imprint
In the output file, output the number of seconds that will elapse from the moment of start to the moment of the first overtaking, with an accuracy of at least 5 digits after the decimal point.
Examples
| # |
Input |
Output |
Explanation |
| 1 |
2
1 3
4 2 |
3.00000 |
In the figure, point A indicates the overtaking place.
 |
| 2 |
2
12 20
221 |
10.00000 |
|