#include <fstream>

using namespace std;
ifstream f("grupuri.in");
ofstream g("grupuri.out");
long long int n,i,k,a[100001],st,dr,m,sol,s,x;
int main()
{
	f>>k>>n;
	for(i=1;i<=n;i++)
	{
	    f>>a[i];
	    s+=a[i];
	}
    st=0;
    dr=s/k;
    while(st<=dr)
    {
        m=(st+dr)/2;
        x=m*k;
        for(i=1;i<=n;i++)x-=min(a[i],m);
        if(x<=0)
        {
            sol=m;
            st=m+1;
        }
        else dr=m-1;
    }
    g<<sol;
    return 0;
}