#include <iostream>
using namespace std;
using ll = long long;
constexpr ll OFFSET = 1e10;
int main()
{
    int N;
    cin >> N;
    ll sum = 0;
    for (int i = 0; i < N; i++) {
        string s;
        cin >> s;
        string st[2];
        int ind = 0;
        for (int i = 0; i < s.size(); i++) {
            if (s[i] == '-') {
                st[0].push_back('-');
                st[1].push_back('-');
                continue;
            }
            if (s[i] == '.') {
                ind = 1;
                continue;
            }
            st[ind].push_back(s[i]);
        }
        ll integer = 0;
        ll floating = 0;
        integer = stoll(st[0]);
        if (not st[1].empty()) {
            const int size = (st[1][0] == '-') ? st[1].size() - 1 : st[1].size();
            for (int i = 0; i < 10 - size; i++) {
                st[1].push_back('0');
            }
            floating = stoll(st[1]);
        } else {
            floating = 0;
        }
        sum += integer * OFFSET + floating;
    }
    const ll integer = sum / OFFSET;
    string floating = to_string(sum % OFFSET);
    const int size = floating.size();
    for (int i = 0; i < 10 - size; i++) {
        floating.push_back('0');
    }
    cout << integer << "." << floating << endl;
    return 0;
}