# -*- 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)
    print('{:.10f}'.format(res))


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