#include <fstream>
using namespace std;


ifstream fin("grupuri.in");
ofstream fout("grupuri.out");

int v[100005], n, k;

int main()
{
    fin>>k>>n;
    long long st=1, dr=0, last=st;
    for(int i=1;i<=n;++i) fin>>v[i], dr+=v[i];
    while(st<=dr)
    {
        int mid=(st+dr)/2;
        long long sum=0;
        for(int i=1;i<=n;++i) sum+=min(v[i], mid);
        if(sum<1LL*mid*k) dr=mid-1;
        else last=mid, st=mid+1;
        //fout<<mid<<" "<<sum<<" "<<mid*k<<" "<<(sum<mid*k)<<" "<<last<<"\n";
    }
    fout<<last<<"\n";
    return 0;
}