#include <iostream>
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
using ll = mp::cpp_int;
using namespace std;
void ins() {}
template<class T,class... Rest>void ins(T& v,Rest&... rest){cin>>v;ins(rest...);}
#define rep(i,n) for(int i=0,_i=(n);i<_i;++i)

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

  ll ans = 0;
  ll integer = 0, decimal = 0;
  rep(i, N) {
    string s; cin >> s;
    bool negative = s[0] == '-';
    if (negative) s = s.substr(1);
    auto pos = s.find(".");

    if (s == "0") continue;
    if (pos == string::npos)
      integer += (negative ? -1 : 1) * stoll(s);
    else {
      integer += (negative ? -1 : 1) * stoll(s.substr(0, pos));
      int len = s.size() - 1 - pos;
      rep(j, 10-len)
        s += "0";
      s = s.substr(pos+1);
      while (!s.empty() && s[0] == '0') s = s.substr(1);
      if (!s.empty())
        decimal += (negative ? -1 : 1) * stoll(s);
    }
  }

  integer += decimal / 10000000000LL;
  decimal %= 10000000000LL;
  if (integer >= 0 && decimal >= 0 || integer <= 0 && decimal <= 0) {
    cout << integer << "." << setfill('0') << setw(10) << abs(decimal) << endl;
  } else {
    if (decimal != 0) --integer;
    cout <<integer<<"." << setfill('0') << setw(10) << 10000000000LL-abs(decimal)<<endl;
  }

  return 0;
}