N=int(raw_input())
A=[raw_input().split(".") for i in range(N)]
asum = 0
bsum = 0
for p in A:
    a = int(p[0])
    b = "0"
    if len(p) > 1:
        b = p[1]
    while len(b) < 10:
        b+="0"
    b = int(b)
    if p[0][0]=='-':
        b*=-1
    asum += a
    bsum += b
asum,bsum
while bsum < 0:
    bsum += 10000000000
    asum -= 1
while bsum >= 10000000000:
    bsum -= 10000000000
    asum += 1
if asum < 0 and bsum > 0:
    asum += 1
    bsum = 10000000000-bsum
bsum = str(bsum)
while len(bsum) < 10:
    bsum = "0"+bsum
print str(asum)+"."+bsum