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C. WTF?

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard output

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

Codeforces (c) Copyright 2010-2018 Mike Mirzayanov

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