#include <fstream>
#include <iostream>
using namespace std;

int main()
{
	ifstream fin("DATA4.txt");
	ofstream fout("OUT4.txt");
	int i,j,hit,num, club[32], dist[5281],t = 5;
	while (t--)
	{
		fin>>hit>>num;
		for (i=0;i<num;i++)
			fin>>club[i];
		dist[0] = 0;
		for (i=1;i<100;i++)
			dist[i] = 100000;
		for (i=0;i<hit;i++)
			for (j=0;j<num;j++)
				if (dist[i+club[j]]>dist[i]+1)
					dist[i+club[j]] = dist[i]+1;
		if (dist[hit]!=100000)
			fout<<dist[hit]<<endl;
		else
			fout<<0<<endl;
	}
	fin.close();
	fout.close();
	return 0;
}