#include <bits/stdc++.h>

using namespace std;

int main() {
	int n, c;
	int p[110];
	cin >> n >> c;
	int sum = 0;
	int ans = 0;
	for (int i = 0; i < c; i++) {
		cin >> p[i];
		sum += p[i];
	}
	ans += sum / (n + 1);
	if (sum % (n + 1) != 0) {
		ans++;
	}
	cout << ans << endl;
	return 0;
}
