n = int(input())
tot = 0
for _ in range(n):
    S = input()
    try:
        ind = S.index(".")
    except:
        ind = len(S)
    S = S[:ind] + S[ind+1:].ljust(10, "0")
    tot += int(S)
tot = str(tot)
minus = False
if tot[0] == "-":
    minus = True
    tot = tot[1:]
tot = tot.zfill(11)
if minus:
    tot = "-" + tot
print(f"{tot[:-10]}.{tot[-10:]}")