from functools import reduce

def convert(x):
    s = x.split('.')
    if len(s) == 2:
        while len(s[1]) < 10:
            s[1] += '0'
        if s[0][0] == '-':
            return int(s[0]) * 10**10 - int(s[1])
        else:
            return int(s[0]) * 10**10 + int(s[1])
    else:
        return int(s[0]) * 10**10

n = int(input())
ans = reduce(lambda x,y:x+y,[convert(input()) for i in range(n)])
if ans < 0:
    print("-%d.%010d" % (-ans // 10**10, -ans % 10**10))
else:
    print("%d.%010d" % (ans // 10**10, ans % 10**10))