(Facebook User Base Growth) There are approximately 2.5 billion people on the Internet as of January 2013. Facebook reached one billion users in October of 2012. In this exercise, you’ll write a program to determine when Facebook will reach 2.5 billion people if it were to grow at fixed monthly percentage rates of 2%, 3%, 4% or 5%.

The input consists of n (0<n<100) lines.
Each line consists of the monthly growth percentage (ranges from 1% to 200%).
The last line of input consists of Int(-1).

Output the minimum number of months that Facebook will need to reach 2.5 billion people.