**The main road from SUSTech to Wavator's home is a straight line from south to north. There are coordinates measured in meters from SUSTech to the ****northernmost(Wavator's home is in the coordinates)****.**

**10 years ago, Wavator only needed to meet his friend Asser in the road, so when they meet, they only calculate their own maximum speed and find a position X that abs(X - X**** **_{Wavator}_{}**) / (V **_{Wavator}**) = abs(X - X **_{Asser}**) / (V **_{Asser}**) so that they can spend the smallest time( abs(X - X _{Wavator}_{}) / (V _{Wavator})) to meet together.**

**But now, Wavator has many friends. ****At some points on the road there are ****n**** friends(contains Wavator), and ****i****-th of them is standing at the point ****xi**** meters and can move with any speed less than or equal to ****vi**** (meters per second) in any of the two directions along the road. ****Wavator wants to celebrate his birthday in any position of the road and he wants to invite all his friends. **

**He knows that his friends are busy so he want to**** compute the minimum time needed to gather all the ****n**** people(n contains himself) at some point on the road. Note that the point they meet at doesn't need to have integer coordinate.**

**Could you help him?**