#include <iostream>
using namespace std;
int main(){
    int N, C;
    cin >> N >> C;
    int p, c = 0;

    for(int i = 1; i <= C; i++){
        cin >> p;
        c += p;
    }
    if(c % (N + 1) == 0) cout << (c / (N + 1)) << endl;
    else cout << (c / (N + 1) + 1) << endl;
}

