import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.Scanner;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String name;
		double salary, totalSalary=0, employeesNum=0;
		Scanner in = new Scanner(System.in);
 
		while (in.hasNext())
		{
			name = in.next();
			salary = in.nextDouble();
			totalSalary+=salary;
			employeesNum++;
		}
		System.out.println(totalSalary/employeesNum);
	}
}

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SXZhbm92IDEwMApJdmFub3YgMzAw

Ivanov 100
Ivanov 300