#include <fstream>
using namespace std;

long long v[1<<17],n,k;

ifstream in("grupuri.in");
ofstream out("grupuri.out");

bool ok(long long x)
{
	long long r=0;
	for (int i=1;i<=n;i++)
		r+=min(v[i],x);
	return r>=x*k;
}

long long bs()
{
	long long i,step=(long long)1<<36;
	for (i=0;step;step>>=1)
		if (ok(i+step))
			i+=step;
	return i;
}

int main()
{
	int i;
	in>>k>>n;
	for (i=1;i<=n;i++)
		in>>v[i];
	out<<bs()<<"\n";
	return 0;
}