#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin ("grupuri.in");
ofstream fout ("grupuri.out");
long long a[100010];
long long n,k,st,dr,mid,i;
int verif(long long poz){
    long long sol=0;
    for(i=1;i<=n;i++)
        sol+=min(a[i],poz);
    if(sol<poz*k)
        return 0;
    return 1;
}
int main()
{
    fin>>k>>n;
    for(i=1;i<=n;i++)
        fin>>a[i];
    st=1;
    dr=100000000000;
    while(st<=dr){
        mid=st+(dr-st)/2;
        if(verif(mid))
            st=mid+1;
        else
            dr=mid-1;
    }
    fout<<dr;
    return 0;
}