#include <iostream>
using namespace std;
int main(){
 int a,b,d,e,f=0;
 cin>>a>>b;
 int c[b];

 for(d=0;d<=b-1;d=d+1){
 cin>>c[d];
}

 for(d=0;d<=b-1;d=d+1){
 f=f+c[d];
}

e=f%(a+1);

if(e!=0){
cout<<1+f/(a+1)<<endl;
}else{
cout<<f/(a+1)<<endl;
}

}
