#include <iostream>
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;

  long long ans = 0;
  rep(i, N) {
    string s; cin >> s;
    auto pos = s.find(".");
    if (s == "0") continue;
    if (pos == string::npos)
      s += "0000000000";
    else {
      int len = s.size() - 1 - pos;
      rep(j, 10-len)
        s += "0";
      s = (s.substr(0, pos) == "0" ? "" : s.substr(0, pos)) + s.substr(pos+1);
    }
    ans += stoll(s);
  }

  string s = to_string(ans);
  if (s.size() == 10)
    cout << "0." << s << endl;
  else if (s[0] == '-' && s.size() == 11)
    cout << "-0." << s.substr(1) << endl;
  else
    cout << s.substr(0, s.size()-10) << "." << s.substr(s.size()-10) << endl;

  return 0;
}