Codeforces Rd #368 (Div. 2) Problem C
In this problem, we have to deal with large integer to get the answer. The key to preserve precision is to use
// operator for integer division because
/ will convert your int to float.
According to Python documentation, int has unlimited precision while float has only 53 bit precision (~15 digits) for integer part.
Notes: For python3. int behaves the same way as long in python 2.