N=int(input())
S=0
for i in range(N):
    A=input()
    if "." in A:

        x=A.index(".")
        A+="0"*(11-len(A)+x)
        #print(x,len(A)-x,A)
        B=""
        for a in A:
            if a!=".":
                B+=a

        #print(B)

        S+=int(B)
    else:
        S+=int(A)*10**10

#print(S)

if S>=0:
    S=str(S)
    while len(S)<11:
        S="0"+S
    S=S[:-10]+"."+S[-10:]
    print(S)
else:
    S=-S
    S=str(S)
    while len(S)<11:
        S="0"+S
    #print(S)
    S=S[:-10]+"."+S[-10:]
    print("-"+S)