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

int main() {
  int n, c, p, sum = 0;
  cin >> n >> c;
  for (int i = 0; i < c; i++) {
    cin >> p;
    sum += p;
  }
  int ans = sum / (n + 1);
  if (sum % (n + 1)) ans++;
  cout << ans << "\n";
}
