#include<cstdio>

using namespace std;

#define IN "grupuri.in","r",stdin
#define OUT "grupuri.out","w",stdout
#define ll long long

int N , K ;
int A[100020];
bool ok = false;
int verifica(ll x)
{
	ll sum = 0;
	for(int i =  1 ; i <= N ; ++i)
		if(A[i] > x)	sum += x;
		else sum += A[i];
	if(sum >= x * K)	return 1;
	else return 0;
}
int main()
{
	freopen(IN);
	freopen(OUT);
	scanf("%d%d",&K,&N);
	for(int i = 1 ; i <= N ; ++i) scanf("%d",&A[i]);	
	ll st = 1  , m , dr = 100000000000LL, sol;
	while(st <= dr)
	{
		m = (st + dr) / 2;
		if(verifica(m) == 1)	{ sol = m; st = m + 1; }
		else dr = m - 1;
	}
	printf("%lld\n",sol);
	return 0;
}