N = int(input())
sm = 0
for i in range(N):
    s = input()
    w = 0
    if s[0] == '-':
        w = 1
        s = s[1:]
    if '.' in s:
        id = s.index('.')
        sm += (-1)**w*int(s[:id]+s[id+1:]+'0'*(10-len(s[id+1:])))
    else:
        sm += (-1)**w*int(s+'0'*10)
ss = str(sm)
ww = ''
if ss[0] == '-':
    ww = '-'
    ss = ss[1:]
if len(ss)<=10:
    ss = '0.'+'0'*(10-len(ss))+ss
    print(ww+ss)
else:
    print(ww+ss[:-10]+'.'+ss[-10:])