import sys
readline=sys.stdin.readline
write=sys.stdout.write

N=int(readline())
ans=0
for i in range(N):
    A=readline().rstrip()
    if "." in A:
        i=A.index(".")
        le=len(A)
        A+="0"*(10-(le-(i+1)))
        le=len(A)
        A=int(A[:i]+A[i+1:le])
    else:
        A=int(A)
        A*=10**10
    ans+=A
sign=1
if ans<0:
    ans*=-1
    sign=-1
ans=str(ans)
if len(ans)<11:
    ans="0"*(11-len(ans))+ans
ans=("-" if sign==-1 else "")+ans[:-10]+"."+ans[-10:]
print(ans)