#include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <complex>
#include <string.h>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <iomanip>
#include <sys/time.h>
#include <random>
#include <stdlib.h>
using namespace std;

#define endl '\n'
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define UNIQ(v) (v).erase(unique((v).begin(), (v).end()), (v).end())

typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;
typedef complex<double> comp;
typedef vector< vector<ld> > matrix;
struct pairhash {
public:
    template<typename T, typename U>
    size_t operator()(const pair<T, U> &x) const {
	size_t seed = hash<T>()(x.first);
	return hash<U>()(x.second) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }
};
const int inf = 1e9 + 9;
const ll mod = 1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1);

int n;
string a[110];

string solve() {
    ll d[n], s[n];
    bool neg[n];
    for (int i = 0; i < n; i++) {
        string t = "";
        int j = 0;
        while (j < a[i].size() && a[i][j] != '.') j++;
        if (a[i][0] == '-') {
            d[i] = stoll(a[i].substr(1, j));
            neg[i] = true;
        } else {
            d[i] = stoll(a[i].substr(0, j));
            neg[i] = false;
        }
        if (j == a[i].size()) {
            s[i] = 0;
        } else {
            string temp = a[i].substr(j+1, a[i].size());
            while (temp.size() < 10) temp += '0';
            s[i] = stoll(temp);
        }
    }

    ll res[2] = {0LL, 0LL};    
    for (int i = 0; i < n; i++) {
        res[0] += (neg[i]?-1:1)*d[i];
        res[1] += (neg[i]?-1:1)*s[i];
    }
    ll m = 1e10;
    stringstream ss;
    if ((res[0] <= 0 && res[1] <= 0) || (res[0] >= 0 && res[1] >= 0)) {
        string sig = "";
        if (res[0] < 0) {
            sig += '-';
            res[0] *= -1;
            res[1] *= -1;
        }
        ss << sig;
        res[0] += res[1] / m;
        res[1] %= m;
    } else {
        if (res[0] >= 0) {
            res[0] -= res[1] / m;
            res[1] %= m;
            res[0]--;
            res[1] = m - res[1];
        } else {
            res[0] += res[1] / m;
            res[1] %= m;
        }
    }

    string q = to_string(res[1]);
    ss << res[0] << ".";
    for (int i = 0; i < 10-(int)q.size(); i++) {
        ss << 0;
    }
    ss << q;
    return ss.str();
}

void input() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);

    input();
    cout << solve() << endl;
}