#region Header #!/usr/bin/env python3 # from typing import * import sys import io import math import collections import decimal import itertools from queue import PriorityQueue import bisect import heapq # def input(): # return sys.stdin.readline()[:-1] input = sys.stdin.readline sys.setrecursionlimit(1000000) #endregion # _INPUT = """# paste here... # """ # sys.stdin = io.StringIO(_INPUT) def main(): N = int(input()) decimal.getcontext().prec = 18 s = decimal.Decimal(0) for _ in range(N): x = decimal.Decimal(int(input())) s += x.sqrt() print(s) if __name__ == '__main__': main()