#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>

using namespace std;

const long long MOVEUP = 1e10;

int main() {
	int n;
	string s;

	long long num1, num2;
	long long ans1 = 0, ans2 = 0;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s;
		int pos = s.find('.');
		if (pos == string::npos) {
			num1 = stoll(s);
			num2 = 0;
		} else {
			num1 = stoll(s.substr(0, pos));
			num2 = stoll(s.append(10, '0').substr(pos + 1, 10));
		}

		ans1 += num1;
		ans2 += (s[0] == '-') ? -num2 : num2;

		if (ans2 < 0) {
			ans1--;
			ans2 += MOVEUP;
		} else if (ans2 >= MOVEUP) {
			ans1++;
			ans2 -= MOVEUP;
		}
	}

	if (ans1 >= 0 || ans2 == 0) {
		printf("%lld.%010lld\n", ans1, ans2);
	} else if (ans1 == -1) {
		printf("-0.%010lld\n", abs(ans2 - MOVEUP));
	} else {
		printf("%lld.%010lld\n", ans1 + 1, abs(ans2 - MOVEUP));
	}

	return 0;
}