Communication System

Time Limit: 10 Seconds
Memory Limit: 32768 KB

We have received an order from Pizoor Communications Inc. for a special communication
system. The system consists of several devices. For each device, we are free
to choose from several manufacturers. Same devices from two manufacturers differ
in their maximum bandwidths and prices.

By overall bandwidth (B) we mean the minimum of the bandwidths of the chosen
devices in the communication system and the total price (P) is the sum of the
prices of all chosen devices. Our goal is to choose a manufacturer for each
device to maximize B/P.

**Input**

The first line of the input file contains a single integer t (1 <= t <=
10), the number of test cases, followed by the input data for each test case.
Each test case starts with a line containing a single integer n (1 <= n <=
100), the number of devices in the communication system, followed by n lines
in the following format: the i-th line (1 <= i <= n) starts with mi (1
<= mi <= 100), the number of manufacturers for the i-th device, followed
by mi pairs of positive integers in the same line, each indicating the bandwidth
and the price of the device respectively, corresponding to a manufacturer.

**Output**

Your program should produce a single line for each test case containing a single
number which is the maximum possible B/P for the test case. Round the numbers
in the output to 3 digits after decimal point.

**Sample Input**

1

3

3 100 25 150 35 80 25

2 120 80 155 40

2 100 100 120 110

**Sample Output**

0.649

Source:

**Asia 2002, Tehran (Iran), Iran Domestic**
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