from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N = int(input())
ans = 0
for _ in range(N):
    
    X = list(input())[:-1]
    now = -1
    n = len(X)
    tmp = ''
    for i in range(n):
        if X[i]=='.':
            now = i
        else:
            if (X[i]=='0')&(tmp==''):
                continue
            tmp += X[i]
    if now==-1:
        X += ['0']*10
        ans += int(''.join(X))
    else:
        
        tmp += '0'*(10 - (n-1 - now))
        ans += int(tmp)
if ans==0:
    print('0.0000000000')
    exit()
ans = list(str(ans))

print(''.join(ans[:-10]+['.']+ans[-10:]))