from decimal import *
N = int(raw_input())
a,b = 0,0.0
for loop in xrange(N):
    n = raw_input()
    if "." in n:
        s = 1 if n[0] != "-" else -1
        i = n.index(".")
        a += int(n[:i])
        b += s*float(n[i:])
    else:
        a += int(n)
    a += int(b)
    b -= int(b)
print str(a+int(str(b)[0]))+("%.10f"%b)[1:]