#include <iostream>

using namespace std;
	
int main ()
{
	int num;
	int sum = 0;
	int counter = 0;
	float avg;

	cin >> num;		
	while (num 1 = -1);
	{
		counter ++;
		sum += sum + num;
		cin >> num;
	}
	
	cout << "average: " << avg << endl;

	return 0;
}