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