#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream>
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>
#include <cstdlib>
using namespace std;
#define Ma_PI 3.141592653589793
#define eps 0.00000000000000000000000001
#define LONG_INF 10000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
int main() {
	int n;
	cin >> n;
	long long a = 0, b = 0;
	REP(i, n) {
		string s;
		cin >> s;
		int multi = 1;
		if (s[0] == '-') multi = -1;
		string big,small;
		int done = 0;
		for (int q = 0;q < s.length();++q) {
			if (s[q] == '.') {
				done = 1;
			}
			else if (done == 0) {
				big.push_back(s[q]);
			}
			else small.push_back(s[q]);
		}
		while (small.size() != 10) {
			small.push_back('0');
		}
		a += stoll(big)*multi;
		b += stoll(small)*multi;
	}
	a += b / 10000000000;
	b = b % 10000000000;
	cout << a << ".";
	string s;
	s = to_string(b);
	while (s.length() != 10) s.push_back('0');
	cout << s;
	cout << endl;
	return 0;
}