# God! Save me

You are located in a room with $n$ doors. If you open the $i$-th door, in $x_{i}$ hours you will be either get to a safe place or you will return to the same room again. What is the expected time $P$ (in hours) until you can move to the safe place?

## Input

The first line is the number of test cases. The first line of each test case contains the value of $n(0<n<100)$. Each of the next $n$ lines contains two numbers $x_{i}(0<∣x_{i}∣<25)$ and $p_{i}(0≤p_{i}≤1)$

if $x_{i}$ is positive, it indicates the time in which you will get to a safe place;

if $x_{i}$ is negative, then $∣x_{i}∣$ indicates the time in which you will return to the room;

The value of $p_{i}$ is the probability to open the $i$-th door. The sum of all $p_{i}$ equals $1$.

## Output

For each test case, first print the serial number of the case, a colon, a space and then print “God! Save me” (without the quotes) if you can't expect to be in the safe place, otherwise print the value of $P$ with $6$ digits after the decimal point.