// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}

ll a[101], b[101];

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  rep(i, n){
    string s;
    cin >> s;
    string t = "";
    bool B = false;
    for(int j = 0; j < sz(s); j++){
      if(s[j] == '.'){
        a[i] = stol(t);
        t = "";
        B = true;
        continue;
      }
      t += s[j];
    }
    if(B){
      t.resize(10, '0');
      b[i] = stol(t);
    }else a[i] = stol(t);
    if(s[0] == '-')b[i] *= -1;
  }
  ll sum1 = 0, sum2 = 0;
  rep(i, n){
    sum1 += a[i];
    sum2 += b[i];
  }
  ll base = (ll)1e10;
  sum1 += sum2 / base;
  if(sum1 >= 0){
    sum2 = sum2 % base;
  }else{
    sum1++;
    sum2 = base - (sum2 % base);
  }
  cout.fill('0');
  cout << sum1 << "." << setw(10) << sum2 << endl;
	return 0;
}