#include <iostream>
#include<algorithm>
using namespace std;
 
int main()
{
    int c,n,a;
    cin >>n>>c;
    int sum=0;
    for (int i = 1; i <= c; i++) {
        cin >> a;
        sum += a;
    }
    int ans = sum / (n + 1);
    if (sum - ans * (n + 1) > 0)ans++;
    cout << ans << endl;
     
}
