#include <iostream>
using namespace std;
int main(void){
    int a,b,c=0;
    cin>>a>>b;
    int d[100];
    for(int i=0;i<b;i++){
        cin>>d[i];
        c=c+d[i];
    }
    if(c%(a+1)==0){cout<<c/(a+1)<<endl;}else{cout<<c/(a+1)+1<<endl;}
}
