# -*- coding: utf-8 -*-
"""
No.81 すべて足すだけの簡単なお仕事です。
https://yukicoder.me/problems/no/81

"""
import sys
from sys import stdin
from decimal import *
input = stdin.readline


def solve(n):
    getcontext().prec = 50
    ans = Decimal(0)
    for _ in range(n):
        ans += Decimal(input())
    return ans


def main(args):
    n = int(input())
    res = solve(n)

    t = str(res)
    if '.' not in t:
        ans = t + '.' + '0'*10
    else:
        a, b = t.split('.')
        if len(b) < 10:
            b = b + '0'*(10-len(b))
        ans = a + '.' + b
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])