HAI

I HAS A TUX

GIMMEH TUX

I HAS A FOO ITS 0

I HAS A BAR ITS 0

I HAS A BAZ ITS 0

I HAS A QUZ ITS 1

TUX IS NOW A NUMBR

IM IN YR LOOP NERFIN YR TUX TIL BOTH SAEM TUX AN 0

I HAS A PUR

GIMMEH PUR

PUR IS NOW A NUMBR

FOO R SUM OF FOO AN PUR

BAR R SUM OF BAR AN 1

BOTH SAEM BIGGR OF PRODUKT OF FOO AN QUZ AN PRODUKT OF BAR BAZ AN PRODUKT OF FOO AN QUZ

O RLY?

YA RLY

BAZ R FOO

QUZ R BAR

OIC

IM OUTTA YR LOOP

BAZ IS NOW A NUMBAR

VISIBLE SMOOSH QUOSHUNT OF BAZ QUZ

KTHXBYE

-----Input-----

The input contains between 1 and 10 lines, i-th line contains an integer number x_{i} (0 ≤ x_{i} ≤ 9).

-----Output-----

Output a single real number. The answer is considered to be correct if its absolute or relative error does not exceed 10^{ - 4}.

-----Examples-----

Input 3 0 1 1

Output 0.666667