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ZOJ Problem Set - 2086
Pressure Calculation

Time Limit: 2 Seconds      Memory Limit: 65536 KB

Cut a round pipe into halves, take away one, and put the other on the plumb plane. Two ends of the half-round pipe are horizontal. Then put 2*n same balls whose radius are equal to the pipe's into the pipe. Be sure the left one and the right one are just tangent with the pipe's ends.
Assume each ball weighs G. Given the number k, you are required to calculate the pressure between the the kth and the (k+1)th ball. (There will be no friction at all.)


Input

Input consists of several test cases. Each case will contain 2 positive integer n and k. (2 <= n <= 100, 1 <= k < 2 * n)

Notice that the left ball marked 1.

The input ends with 0 0.


Output

Output the pressure between the the kth and the (k+1)th ball. Check it in the sample. Accurate to 2 decimal places.


Sample Input

2 1
100 2
0 0


Sample Output

1.00 G
2.00 G



Author: YU, Xing
Source: ZOJ Monthly, February 2004
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