import java.util.Scanner;

class Numbers {
	double avg = 0.0;

	int sumInNumbers() {
		// Read as many numbers as given on stdin
		// and return the count of numbers.
		// Maximum numbers that can be taken is MAX
		int count = 0;
		Scanner in = new Scanner(System.in);
		while (in.hasNextInt()) {
			avg = ((avg * count) + in.nextInt())/(count+1);
			count = count +1;
		}
		return count;
	}
	public static void main(String args[]) {
		Numbers n = new Numbers();
		int sz = n.sumInNumbers();
		if (sz == 0) {
			System.err.println("Not Enough Numbers");
			return;
		}
		System.out.println("Average: " + n.avg);
	}
}