越狱

Grade Open Time Friday, 19 September 2014, 10:05 am
Discount 0.8 Time Discount Friday, 26 September 2014, 10:05 am
Allow late Yes Close Time Friday, 26 September 2014, 10:05 am
Input file prisona.in Output file prisona.out

[HNOI2008]越狱



Sample Input

2 3

Sample Output

6

HINT


6种状态为(000)(001)(011)(100)(110)(111)