#include <iostream>
using namespace std;
const int N = 11;

int m, n, res, a[N];

int main()
{
	cin >> m >> n;
	for (int i = 1; i <= n; i ++ ) cin >> a[i];
	for (int i = n; i > 0; i -- )
		if (m % a[i] != m) res += m / a[i], m %= a[i];
	if (m) puts("Impossible");
	else cout << res << endl;
}