#include <iostream>
#include <string>
#include <cmath>
using namespace std;

signed main() {
	int n;
	cin >> n;
	
	long long ans_i = 0;
	long long ans_f = 0;
	
	while (n--) {
		string s;
		int i;
		long long tmp_i = 0, tmp_f = 0;	//tmp_i + tmp_f * 10^(-10)が与えられた！！
		
		cin >> s;
		for (i = (s[0] == '-'); i < s.length() && s[i] != '.'; i++) { tmp_i *= 10; tmp_i += s[i] - '0'; }
		if (s[i] == '.') { i++; }
		
		int shift = 10 - ((int)s.length() - i);
		for (; i < s.length(); i++) { tmp_f *= 10; tmp_f += s[i] - '0'; }
		for (i = 0; i < shift; i++) { tmp_f *= 10; }
		
		ans_i += (s[0] == '-') ? -tmp_i : tmp_i;
		ans_f += (s[0] == '-') ? -tmp_f : tmp_f;
		
		if (ans_f >= 10000000000) { ans_i++; ans_f -= 10000000000; }	//桁上がり
		if (ans_f < 0) { ans_i--; ans_f += 10000000000; }
		//cout << ans_i << " " << ans_f << endl;
	}
	
	if (ans_i >= 0) printf("%lld.%010lld\n",ans_i, ans_f);
	else {
		if (ans_f < 0) printf("-%lld.%010lld\n", abs(ans_i), abs(ans_f));
		else printf("-%lld.%010lld\n", abs(ans_i + 1), abs(ans_f - 10000000000));
	}
	return 0;
}