#include <fstream>

using namespace std;

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

long long k, n, v[100100], i, g, l, r, m, sol;

bool sePoate(long long x)
{
    long long s = 0;
    for (i = 1; i <= n; i++) {
        if (v[i] < x)
            s += v[i];
        else
            s += x;
    }
    if (s >= k * x)
        return true;
    return false;
}

int main()
{
    fin >> k >> n;
    for (i = 1; i <= n; i++)
        fin >> v[i];
    l = 0;
    r = 100000000000;
    while (l <= r) {
        m = (l + r) / 2;
        if (sePoate(m)) {
            sol = m;
            l = m + 1;
        }
        else
            r = m - 1;
    }
    fout << sol;
    fin.close();
    fout.close();
    return 0;
}
/*#include <iostream>
#include <fstream>

#define Nmax 100000
using namespace std;
ifstream fin ("grupuri.in");
ofstream fout ("grupuri.out");
int n,k,i;
long long l,r,m,x,sol;
const long long Amax=1000000;
int v[Nmax];
int main()
{
    fin>>k>>n;
    for (i=0;i<n;i++)
        fin>>v[i];
    l=0;
    r=Nmax*Amax;
    while (l<=r)
    {
        m=(l+r)/2;
        x=0;
        for (i=0;i<n;i++)
        {
            if (v[i]<k)
                x+=v[i];
            else x+=k;
        }
        if (x>=m*k)
        {
            l=m+1;
            sol=m;
        }
        else r=m-1;
    }
    fout<<sol;
    return 0;
}*/