#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

int main()
{
    int n;
    cin >> n;

    long long a = 0;
    long long b = 0;
    for(int i=0; i<n; ++i){
        string s;
        cin >> s;
        int k = s.find('.');
        if(k == string::npos){
            a += stoll(s);
        }
        else{
            string x = s.substr(0, k);
            string y = s.substr(k+1);
            y.resize(10, '0');
            a += stoll(x);
            if(s[0] == '-')
                b -= stoll(y);
            else
                b += stoll(y);
        }
    }

    a += b / 10000000000;
    b %= 10000000000;
    cout << a << '.' << setfill('0') << setw(10) << b << endl;

    return 0;
}