def duanxin_shuliang(n): results=[] for x in range(n): a=int(input()) results.append(a) return results def feiyong(results): cnt=0 for result in results: if result%70!=0: a=result//70+1 else: a=result//70 cnt+=a*0.1 return "{:.1f}".format(cnt) n=int(input()) results=duanxin_shuliang(n) print(feiyong(results))