DWITE Online Computer Programming Contest, October 2007, Problem 4

Some kids play with blocks, and build things by stacking different blocks on top of each other. Given a set of blocks and a target height, we want to find out if it's possible to construct a stack with an exact specified height.

The input will contain at least $3$ lines, one positive integer value per line. The first line will contain an integer $H$, the target height for the stack. $0\le H\le 100$

The second line will contain an integer $S$, number of blocks in a set. $0\le S\le 10$

The next $S$ lines will contain integers, one per line; $0\le N\le 10$; representing the height of blocks in the set.

The output file will contain a single integer value, a minimum number of blocks out of the supplied set, required to build a stack of the given height. If it is impossible to build the desired stack, output $0$.

Sample Input 1

5
3
1
2
3

Sample Output 1

2

Sample Input 2

10
3
1
5
7

Sample Output 2

0

Problem Resource: DWITE