n = int(raw_input())

这会将输入转换为整数.由于Python采用任意精度算法，因此我们不必担心数字有多大.

This will convert the input to an integer. Since Python employs arbitrary precision arithmetic, we don't have to worry about how big the number is.

>>> n = int(raw_input())
100000000000000
>>> n
100000000000000L