#include "bits/stdc++.h"
using namespace std;
     
#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl
     
typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll, ll>
const int inf = 1000000001;
const ll INF = 1e16;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<<fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };


ll getsum(vs s) {
  ll res = 0;
  for (int i = 0; i < s.size(); i++) {
    res += stoll(s[i]);
  }
  return res;
}

int main() {
  int n, i, j;
  cin >> n;
  vs sei, fu;
  for (i = 0; i < n; i++) {
    string s;
    cin >> s;
    if (s[0] == '-') {
      fu.push_back(s);
    }
    else {
      sei.push_back(s);
    }
  }
  vs seiji;
  vs seisyo;
  for (i = 0; i < sei.size(); i++) {
    for (j = 0; j < sei[i].size(); j++) {
      if (sei[i][j] == '.') {
	seisyo.push_back(sei[i].substr(j + 1, sei[i].size() - j - 1));
	while (seisyo[seisyo.size() - 1].size() < 10) {
	  seisyo[seisyo.size() - 1].push_back('0');
	}
	sei[i] = sei[i].substr(0, j);
      }
    }
    seiji.push_back(sei[i]);
  }
  vs fuji;
  vs fusyo;
  for (i = 0; i < fu.size(); i++) {
    fu[i].erase(fu[i].begin());
    for (j = 0; j < fu[i].size(); j++) {
      if (fu[i][j] == '.') {
	fusyo.push_back(fu[i].substr(j + 1, fu[i].size() - j - 1));
	while (fusyo[fusyo.size() - 1].size() < 10) {
	  fusyo[fusyo.size() - 1].push_back('0');
	}
	fu[i] = fu[i].substr(0, j);
      }
    }
    fuji.push_back(fu[i]);
  }
  
  // DEBUG_VEC(seiji);
  // DEBUG_VEC(seisyo);
  // DEBUG_VEC(fuji);
  // DEBUG_VEC(fusyo);
  
  ll seisum1 = 0, seisum2 = 0;
  ll fusum1 = 0, fusum2 = 0;
  seisum1 = getsum(seiji);
  seisum2 = getsum(seisyo);
  fusum1 = getsum(fuji);
  fusum2 = getsum(fusyo);
  // DEBUG(seisum1);
  // DEBUG(seisum2);
  // DEBUG(fusum1);
  // DEBUG(fusum2);
  pll S = pll(seisum1, seisum2);
  pll F = pll(fusum1, fusum2);
  while (S.second >= 10000000000) {
    S.second -= 10000000000;
    S.first++;
  }
  while (F.second >= 10000000000) {
    F.second -= 10000000000;
    F.first++;
  }
  bool flag = true;
  if (S == F) {
    cout << "0.0000000000" << endl;
    return 0;
  }
  else if (S < F) {
    swap(S, F);
    flag = false;
  }
  if (S.second >= F.second) {
    S.second -= F.second;
  }else {
    S.first--;
    S.second += 10000000000 - F.second;
  }
  S.first -= F.first;
  if (!flag) {
    printf("-");
  }
  printf("%lld.%010lld\n",S.first, S.second);
}