Problem:       
    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 xi (0 ≤ xi ≤ 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

Solution (in JAVA):

Solution:
import java.util.*;
import java.math.*;
import java.io.*;

public class Main{
	static String s[] = new String[33];
	public static void main(String args[]) throws IOException {
		//BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		Scanner in = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int tux, foo, bar, baz, quz, pur;
		bar = 0; baz = 0; foo = 0; quz = 1;
		tux = in.nextInt();
		for(; tux > 0; tux--){
			pur = in.nextInt();
			foo += pur; bar++;
			if(foo * quz >= bar * baz){
				baz = foo;
				quz = bar;
			}
			
		}
		double ans = (double)baz;
		ans /= (double)quz;
		out.println(ans);
		out.flush();
	}
}