      
    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
import java.util.Scanner;
import java.io.*;

// The "ProblemC" class.
public class ProblemC
{
    public static void main (String[] args) throws IOException
    {
		//Scanner inFile = new Scanner(new File("DATA_C.txt"));
		Scanner inSys = new Scanner(System.in);
		//PrintStream outFile = new PrintStream(new File("OUT_C.txt"));
		PrintStream outSys = new PrintStream(System.out);
		
		//int numloops = Integer.parseInt(inFile.nextLine());
		int numloops = Integer.parseInt(inSys.nextLine());
		int sum = 0;
		int[] nums = new int[numloops];
		
	
		for(int i = 0; i < numloops; i++)
		{
			//nums[i] = Integer.parseInt(inFile.nextLine());
			nums[i] = Integer.parseInt(inSys.nextLine());
		}
		
		int x = 0;
		if(numloops > 1)
		{
			while(nums[x] <= nums[x+1])
			{
				x++;
				if(x == (numloops-1))
				{
					break;
				}
			}
			x++;
			
			
			for(int i = 0; i < x; i++)
			{
				sum+=nums[i];
			}
			
			if(x != 0)
			{
				System.out.println(1.0 * sum / x);
			}
			else
			{
				System.out.println("0");
			}
		}
		else
		{
			System.out.println(nums[0]);
		}
    } // main method
} // ProblemC class
