Statement

It's the world tourism day and agoda has launched a special promocode with each hotel booking a person makes, they can get a cashback randomly and uniformly distributed from the range [1, maxCashback] in integer USD. A person will start with 0 cashback and can keep applying this promocode until they secure a minimum of M USD in total across all his future bookings.

To keep the customers happy, Agoda wants to ensure that majority of people can make atleast H USD from this promocode.
Find the probability of a customer being not happy (total cashback < H) with this promocode. Given M, maxCashback, H.

Constraints

0 <= M <= H <= 1e4

1 <= maxCashback <= 1e4

Output

The calculated probability

SAMPLE TEST CASE

1 10 6

OUTPUT

0.50000