#include <fstream>

using namespace std;

ifstream fin ("grupuri.in");

ofstream fout ("grupuri.out");

int main () {

	int k, n;

	fin >> k >> n;

	long long v[n + 1];

	for (int i = 1; i <= n; ++i)
		fin >> v[i];

	long long x = 0, st = 1, dr = 1e12;

	while (st <= dr) {

		long long mij = st + (dr - st) / 2;

		long long total = 0;

		for (int i = 1; i <= n; ++i)
			total += min (v[i], mij);

		if (total < mij * k)
			dr = mij - 1;
		else {

			x = mij;

			st = mij + 1;
		}
	}

	fout << x;

	return 0;
}