You are located in a room with doors. If you open the -th door, in hours you will be either get to a safe place or you will return to the same room again. What is the expected time (in hours) until you can move to the safe place?
The first line is the number of test cases. The first line of each test case contains the value of . Each of the next lines contains two numbers and
if is positive, it indicates the time in which you will get to a safe place;
if is negative, then indicates the time in which you will return to the room;
The value of is the probability to open the -th door. The sum of all equals .
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 with digits after the decimal point.