URI Problem (Ages) 1154:
Ages is a basic problem on URI online judge for novice problem solver.
You can find details on this Link.

import java.util.Scanner;

/**
 * @Author : Muhammad Harun-Or-Roshid
 * @E-mail : [email protected]
 * @Date   : Oct 21, 2016
 * @Time   : 10:20:55 PM
 */
public class Uri1154 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int total = 0, count = 0 ;
        while(true){
            int age = sc.nextInt();
            if(age<0){
                break;
            }else{
                total+=age;
                count++;
            }         
        }
        double x = total/(double)count;
        System.out.printf("%.2f\n",x);
    }
}