import java.util.*;	
	
public class NumberAverage {

	public static void main(String[] args) {

		int valuesProcessed = 0;
		double valueSum = 0;
		
		// set up the input
		Scanner stdin = new Scanner (System.in);
		
		// prompt user for values
		System.out.println("Enter positive numbers 1 per line.\n"
		  + "Indicate end of the list with a negative number.");
		
		// get first value
		double value = stdin.nextDouble();
		
		// process values one-by-one
		while (value >= 0) {
			valueSum += value;
			++valuesProcessed;
			value = stdin.nextDouble();
		}
		
		// display result
		if (valuesProcessed > 0) {
			double average = valueSum / valuesProcessed;
			System.out.println("Average: " + average);
		} else {
			System.out.println("No list to average");
		}

	}
}