#P1351. Number of Locks
Number of Locks
Description
In certain factory a kind of spring locks is manufactured. There are n slots (1 < n < 17, n is a natural number.) for each lock. The height of each slot may be any one of the 4 values in{1,2,3,4}( neglect unit ). Among the slots of a lock there are at least one pair of neighboring slots with their difference of height equal to 3 and also there are at least 3 different height values of the slots for a lock. If a batch of locks is manufactured by taking all over the 4 values for slot height and meet the two limitations above, find the number of the locks produced.
Input
There is one given data n (number of slots) on every line. At the end of all the input data is -1, which means the end of input.
Output
According to the input data, count the number of locks. Each output occupies one line. Its fore part is a repetition of the input data and then followed by a colon and a space. The last part of it is the number of the locks counted.
2
3
-1
2: 0
3: 8
Source
Xi'an 2002