#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N;
	while(~scanf("%d", &N)) {
		const ll D = 10000000000LL;
		ll A = 0, B = 0;
		rep(i, N) {
			string s;
			cin >> s;
			bool sign = s[0] == '-';
			if(sign)
				s = s.substr(1);
			ll a, b;
			size_t point = s.find('.');
			if(point == string::npos) {
				sscanf(s.c_str(), "%lld", &a);
				b = 0;
			}else {
				sscanf(s.c_str(), "%lld.%lld", &a, &b);
				int e = 11 - (int)(s.size() - point);
				rep(j, e)
					b *= 10;
			}
			if(!sign)
				A += a, B += b;
			else
				A -= a, B -= b;
		}
		ll d = B / D - (B < 0 && B % D != 0);
		A += d;
		B -= d * D;
		if(A >= 0) {
			printf("%lld.%010lld\n", A, B);
		} else {
			if(B != 0)
				++ A, B = D - B;
			printf("-%lld.%010lld\n", abs(A), B);
		}
	}
	return 0;
}