Problem9674--ABC184 —— D - increment of coins

9674: ABC184 —— D - increment of coins

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Time Limit : 1.000 sec  Memory Limit : 512 MiB

Description

We have a bag containing $A$ gold coins, $B$ silver coins, and $C$ bronze coins.

Until the bag contains $100$ coins of the same color, we will repeat the following operation:

Operation: Randomly take out one coin from the bag. (Every coin has an equal probability of being chosen.) Then, put back into the bag two coins of the same kind as the removed coin.

Find the expected value of the number of times the operation is done.

Input

Input is given from Standard Input in the following format:

```
$A$ $B$ $C$
```

Output

Print the expected value of the number of times the operation is done. Your output will be accepted if its absolute or relative error from the correct value is at most $10^{-6}$.

Constraints

-   $0 \leq A,B,C \leq 99$
-   $A+B+C \geq 1$

Sample 1 Input

99 99 99

Sample 1 Output

1.000000000
No matter what coin we take out in the first operation, the bag will contain 100 coins of that kind.

Sample 2 Input

98 99 99

Sample 2 Output

1.331081081
We will do the second operation only if we take out a gold coin in the first operation. Thus, the expected number of operations is $2×\frac{98}{98+99+99}+1×\frac{99}{98+99+99}+1×\frac{99}{98+99+99}=1.331081081…$

Sample 3 Input

0 0 1

Sample 3 Output

99.000000000
Each operation adds a bronze coin.

31 41 59

91.835008202

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