9363: CCC '22 S1 - Good Fours and Good Fives
[Creator : ]
Description
Finn loves Fours and Fives. In fact, he loves them so much that he wants to know the number of ways a number can be formed by using a sum of fours and fives, where the order of the fours and fives does not matter. If Finn wants to form the number 14, there is one way to do this which is 14=4+5+5. As another example, if Finn wants to form the number 20, this can be done two ways, which are 20=4+4+4+4+4 and 20=5+5+5+5. As a final example, Finn can form the number 40 in three ways: 40=4+4+4+4+4+4+4+4+4+4, 40=4+4+4+4+4+5+5+5+5, and 40=5+5+5+5+5+5+5+5.
Your task is to help Finn determine the number of ways that a number can be written as a sum of fours and fives.
Input
The input consists of one line containing a number $N\ (1 \leq N \leq 1,000,000)$.
Output
Output the number of unordered sums of fours and fives which form the number $N$. Output 0 if there are no such sums of fours and fives.
Sample 1 Input
14
Sample 1 Output
1
This is one of the examples in the problem description.
Sample 2 Input
40
Sample 2 Output
3
Sample 3 Input
6
Sample 3 Output
0
There is no way to use a sum of fours and fives to get 6.
HINT
相同题目:CCC22s1。