#include <fstream>
#include <algorithm>

#define int long long

using namespace std;

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

int n, k;
int ans;
int v[100005];

bool possible(int x)
{
    int cntAnimals = 0;
    for(int i = 1; i <= n; i++)
        cntAnimals += min(v[i], x);
    return cntAnimals >= x*k;
}

int32_t main()
{
    in >> k >> n;
    for(int i = 1; i <= n; i++)
        in >> v[i];
    sort(v+1, v+n+1);
    for(int step = (1LL << 60); step; step >>= 1)
        if(possible(ans+step))
            ans += step;
    out << ans;
    return 0;
}