import math

n = int(raw_input())

seisu = 0
syousu = 0.0

for i in xrange(n):
    inp = raw_input()
    if "." in inp:
        sp = inp.split(".")
        seisu+=int(sp[0])
        if sp[0][0]=="-":
            syousu-=round(float("0."+sp[1]),10)
        else:
            syousu+=round(float("0."+sp[1]),10)
            # print syousu
    else:
        seisu+=int(inp)

    # s = round(s+float(raw_input()),10)
    # print seisu
# print str(syousu).split(".")[0]
print str(seisu+int(str(syousu).split(".")[0]))+"."+"{0:.10f}".format(syousu).split(".")[1]

# print "{0:.10f}".format(s)
# print math.modf(round(99999999.999999999,10))

# print "{0:.10f}".format(round(1.00000000-0.999999999,10))