#include<cstdio>
int a[100001],n,i,k,st,dr,mij,x;
long long s;
int check(int m)
{
	int  x=m*k;
	for(i=1;i<=n && x>0;i++)
		if(a[i]>m) x-=m;
		else x-=a[i];
	return x<=0;
}
int search(int st,int dr)
{
	if(st==dr) if(check(st)) return st; else return 0;
	int mij=(st+dr)>>1;
	if(check(mij)){
		int k=search(mij+1,dr);
		if(k) return k;
		else return mij;}
	else
		return search(st,mij-1);		
}
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]);
		s+=a[i];}
	printf("%d\n",search(1,s/k));
	fclose(stdout);
	return 0;
}