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