#include <iostream>
using namespace std;

int main(){
    int N,C;

    cin >> N >> C;

    int p[C];
    int H=0;

    for(int i=0;i<C;i++){
        cin >> p[i];
        H=H+p[i];
    }

    if(H%(N+1)==0){
        cout << H/(N+1)<< endl;
    }else{
        cout << H/(N+1)+1 << endl;
    }

    return 0;

    }


