#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)


void printans(string ans[], int h, int w, int s)
{
    if (!s)
    {
        rep(i, h)
        {
            cout << ans[i] << endl;
        }
    }
    else
    {
        rep(i, w)
        {
            rep(j, h)
            {
                cout << ans[j][i];
            }
            cout << endl;
        }
    }
}

int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int n, sign, dot;
    cin >> n;
    ll ansd, ansf;
    string s, sd, sf;
    ansd = ansf = 0;

    rep(i, n)
    {
        sign = 0, dot = 0;
        cin >> s;
        if (s[0] == '-')
            sign = 1;
        rep(i, s.length())
        {
            if (s[i] == '.')
            {
                dot = i;
                break;
            }
        }

        if (!dot)
        {
            if (sign)
                ansd -= stoll(s.substr(sign, (s.length() - sign)));
            else
                ansd += stoll(s.substr(sign, (s.length() - sign)));
        }

        else
        {
            if (sign)
                ansd -= stoll(s.substr(sign, (dot - sign)));
            else
                ansd += stoll(s.substr(sign, (dot - sign)));

            sf = s.substr(dot + 1, (s.length() - dot - 1));

            rep(i, 10)
                sf += '0';
            sf = sf.substr(0, 10);

            if (sign)
                ansf -= stoll(sf);
            else
                ansf += stoll(sf);
        }
    }

    ansd += ansf / 10000000000ll;
    ansf %= 10000000000ll;

    if (ansf == 0)
        sf = "0";
    else
    {
        sf = "";
        while (ansf)
        {
            sf += '0' + (ansf % 10);
            ansf /= 10;
        }
    }
    reverse(sf.begin(), sf.end());
    rep(i, 10)
        sf += '0';
    sf = sf.substr(0, 10);

    cout << ansd << "." << sf << endl;

    return 0;
}