#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using i128 = __int128_t;
using ld = long double;

const i128 b = 1e10;

int main(void) {
	int N;
	cin >> N;
	
	vector<ld> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];
	
	i128 ans = 0;
	for(int i = 0; i < N; ++i) ans += (i128)(A[i] * b);
	cout << (ll)(ans / b) << "." << (ll)(ans % b) << "\n";
	return 0;
}