#include <bits/stdc++.h>
using namespace std;

ifstream f("grupuri.in");
ofstream g("grupuri.out");

long long k, n;
long long rez, sus, x[100005];

void solve(long long n, long long k)
{
    if (n<0 || rez<0)
        {
            g << 0;
            return;
        }
    if (x[n]<=rez/k)
        {
            g << rez/k;
            return;
        }
    rez-=x[n];
    solve(n-1,k-1);
}

int main( )
{
    f >> k >> n;
    for (long long i=1; i<=n; ++i)
    {
        f >> x[i];
        rez+=x[i];
    }
    solve(n,k);
    return 0;
}