#include <bits/stdc++.h>

using namespace std;

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	__int128 sum = 0;
	int n;
	long double t;

	cin >> n;

	for (int i = 0; i < n; i++)
	{
		cin >> t;
		t *= 10000000000;
		__int128 temp = t;
		sum += t;
	}

	long double res = sum;
	//cout << res << '\n';
	res/=10000000000;

	cout << fixed;
	cout.precision(10);

	cout << res << '\n';

	return 0;
}