#include<bits/stdc++.h> using namespace std; double p(int n,int a[]){ double s = 0; for(int i = 0;i < n;i++){ int tiao = (a[i] + 69)/70; s = s+tiao*0.1; } return s; } int main(){ int n; cin>>n; int a[1000]; for(int i = 0;i < n;i++){ cin>>a[i]; } double m = p(n,a); cout<<fixed<<setprecision(1)<<m; return 0; }