#include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <map>
#include <vector>
#include <cmath>
#include <cstdlib>

using namespace std;

#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define REPO(i, n) for(int i = 1;i <= n;i++)
#define ll long long
#define INF 1999999999
#define MINF -1999999999

int main() {
	int a,b,c,d = 0;
	cin >> a >> b;
	REP(i, b) {
		cin >> c;
		d += c;
	}
	cout << (d + a) / (a + 1) << endl;
}
