#include<stdio.h>

int a[100001];
int n,k,i;
long long sum, low, high, mid, aux;

int solve(long long p)
{
	aux=p*k;
	int i;
	for(i=1;i<=n&&aux>0;i++)
		if(a[i]>p)
			aux-=p;
		else aux-=a[i];
	if(aux<=0)
		return 1;
	else return 0;
}


int main()
{
	freopen("grupuri.in", "r", stdin);
	freopen("grupuri.out", "w", stdout);
	scanf("%d%d", &k, &n);
	for(i=1;i<=n;i++)
	{
		scanf("%d", &a[i]);
		sum+=a[i];
	}
	low=1; high=sum/k;
	while(high-low>1)
	{
		mid=(low+high)/2;
		if(solve(mid))
			low=mid;
		else high=mid-1;
	}
	if(!solve(low)) low=0;
	if(high>low&&solve(high)) low=high;
	printf("%lld\n", low);
	return 0;
}