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

using namespace std;
const long long convert = 1e10;

int main() {
	int n;
	string s;
	long long ans1 = 0; // 整数部
	long long ans2 = 0; // 小数部
	long long tmp;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s;

		int pos = s.find('.', 0);
		ans1 += atol(s.substr(0, pos).c_str());

		if (pos != string::npos) {
			tmp = atof(s.substr(pos).c_str()) * convert;
			ans2 += (long long) (s[0] == '-' ? -tmp : tmp);
		}
	}

	// 0 <= ans2 < 1e10 にする
	if (ans2 < 0) {
		ans1 += floor(1.0 * ans2 / convert);
		ans2 -= floor(1.0 * ans2 / convert) * convert;
	} else {
		ans1 += ans2 / convert;
		ans2 -= ans2 / convert * convert;
	}
	// ans1 ans2の符号を同じにする
	if (ans1 < 0) {
		ans1++;
		ans2 -= convert;
	}

	if (ans1 == 0 && ans2 < 0) {
		printf("-");
	}
	printf("%lld.%010lld\n", ans1, abs(ans2));
	return 0;
}