import bisect import copy import decimal import fractions import functools import heapq import itertools import math from operator import is_ import random import sys from collections import Counter,deque,defaultdict from functools import lru_cache,reduce from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max def _heappush_max(heap,item): heap.append(item) heapq._siftdown_max(heap, 0, len(heap)-1) def _heappushpop_max(heap, item): if heap and item < heap[0]: item, heap[0] = heap[0], item heapq._siftup_max(heap, 0) return item from math import gcd as GCD read=sys.stdin.read readline=sys.stdin.readline readlines=sys.stdin.readlines def Bisect_Int(ok,ng,is_ok): while abs(ok-ng)>1: mid=(ok+ng)//2 if is_ok(mid): ok=mid else: ng=mid return ok N=int(readline()) ans=0 decimal.getcontext().prec=18 for _ in range(N): x=int(readline()) x*=10**36 def is_ok(n): return n**2<=x ans+=decimal.Decimal(Bisect_Int(0,1<<90,is_ok))/10**18 print(ans)