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#include<iostream>
#include<cmath>
using namespace std;
int main(){
int n;
cin>>n;
int count=0; //总短信数
double cost=0;
for(int i=0,x;i<n;i++){
cin>>x;
count+=ceil((double)x/70); //向上取整
}
cost=count*0.1;
cout<<cost<<endl;
return 0;
}