Alphanumeric Password Probability

You are given several test cases. In each test case, you are provided with an integer n representing the number of login attempts. For each attempt, you are given a pair of integers P_i and C_i. The integer P_i represents the chance (in percentage) that the attempt will yield an alphanumeric password. Note that C_i is also provided as an identifier (0 or 1) but is not used in the calculation.

Your task is to compute the probability that the next login attempt produces an alphanumeric password. Mathematically, for a given test case with n attempts, the probability is calculated as:

$$\text{Probability} = \frac{1}{n}\sum_{i=1}^{n} \frac{P_i}{100} $$

Output the probability for each test case rounded to 9 decimal places.

inputFormat

The first line contains an integer T, the number of test cases. For each test case, the first line contains an integer n, the number of login attempts. This is followed by n pairs of integers Pi and Ci separated by spaces.

outputFormat

For each test case, print the computed probability on a new line. The probability must be rounded to 9 decimal places.

## sample

4
3
70 1 30 0 50 1
2
45 0 90 1
4
100 1 100 1 100 1 100 1
4
0 0 0 0 0 0 0 0

0.500000000
0.675000000
1.000000000
0.000000000

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