// unsolved
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll INF = 1LL << 60;

int main() {
  int n;
  cin >> n;
  ll ans1 = 0, ans2 = 0;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    ll d = 1;
    if (s[0] == '-') d = -1;
    int pos = s.rfind('.');
    if (pos == -1) {
      ans1 += stoi(s);
    } else {
      for (int j = 0; j < pos; j++) {
        if (j == 0 && d == -1) continue;
        ans1 += (s[j] - '0') * pow(10, pos - j - 1) * d;
      }
      for (int j = pos + 1; j < s.size(); j++) {
        ans2 += (s[j] - '0') * pow(10, 9 - (j - pos) + 1) * d;
      }
    }
  }
  cout << ans1 + ans2 / ll(1e10) << ".";
  cout << setfill('0') << left << setw(10) << abs(ans2) % ll(1e10) << endl;
}