#include <bits/stdc++.h>

using namespace std;
#define ll long long
int n, k;
const int MAXN = 1e5;
int a[MAXN + 1];
bool check (ll kek) {
  int i;
  ll nr, ind;
  ind = 0;
  nr = 1;
  for (i = 1; i <= n; i++) {
    ind += min (kek, 1LL * a[i]);
    if (ind >= kek) {
      nr++;
      ind -= kek;
    }
  }
  return nr > k;
}

int main() {
  ll st, dr, sol;
  int i;
  freopen ("grupuri.in", "r", stdin);
  freopen ("grupuri.out", "w", stdout);
  scanf ("%d%d", &k, &n);
  for (i = 1; i <= n; i++)
    scanf ("%d", &a[i]);
  st = 0;
  dr = 1e11;
  while (st <= dr) {
    ll mij = (st + dr) / 2;
    if (check (mij) == true) {
      sol = mij;
      st = mij + 1;
    }
    else
      dr = mij - 1;
  }
  printf ("%lld\n", sol);
  return 0;
}