0000 I comment out my debugging prints.

 0001 I do not mix tokens and lines.

 0010 I do not mix bitwise and arithmetic operations.

 0011 I use *long* where *int* will not do.

 0100 I use *BigInteger* where *long* will not do.

 0101 I account for every number in the problem description.

 0110 I am wary of memory consumption.

 0111 I am wary of overflow.

 1000 I am wary of input order.

 1001 I know that *String* is immutable.

 1010 I ensure I read what I presume.

 1011 I input and output to a file or stdin/stdout as required.

 1100 I tried all input cases (as feasible).

 1101 I tried the worst case (as feasible).

 1110 I have used clean newlines.


 1111 I have dotted every i and crossed every t.