#include <iostream>
#include <iomanip>
using namespace std;
int main(){
    int n,x,sum=0;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>x;
        while(x>0){
            x-=70;
            sum++;
        }
    }
    cout<<fixed<<setprecision(1)<<sum*0.1<<endl;
    return 0;
}