from Queue import * # Queue, LifoQueue, PriorityQueue
from bisect import * #bisect, insort
from collections import * #deque, Counter,OrderedDict,defaultdict
#set([]) 
import math
import copy
import itertools
import string
import sys
myread = lambda : map(int,raw_input().split())
def ten_times(s):
    ret = 1
    if s[0] == '-':
        ret = -1
        s = s[1:]
    while s:
        if s[0] == '0':
            s = s[1:]
        else:
            break
    
    x = s.find('.')
    if x == -1:
        ret *= int(s+('0'*10))
    else:
        times = 10-(len(s)-x-1)
        #print len(s),x,times
        s = s[:x]+s[x+1:] + ('0' *times)
        ret *= int(s)
    #print ret
    return ret
def dot_insert(x):
    s = str(x)
    #print s
    if len(s) >= 11:
        return s[:-10]+'.'+s[-10:]
    else:
        '0'+'.'+('0'*10-len(s))+s
        
def solver():
    N = int(raw_input())
    ans = 0
    for _ in xrange(N):
        ans += ten_times(raw_input())
    print dot_insert(ans)

        
if __name__ == "__main__":
    solver()