#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <set>
#include <algorithm>
#include <functional>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cctype>
#include <string>
#include <cstring>

using namespace std;

typedef long long ll;

bool compare(const double a, const double b) {
  return fabs(a) < fabs(b);
}

int main() {
  int n;
  cin >> n;
  long double a[n], b[n];
  long double ans = 0;
  for (int i = 0; i < n; i++) {
    long double x;
    cin >> x;
    b[i] = modfl(x, &a[i]);
  }

  sort(a, a+n);
  sort(b, b+n, compare);

  long double sum1 = 0, sum2 = 0, sum3 = 0, sum4 = 0;
  for (int i = 0; i < n; i++) {
    sum1 += a[i];
    sum2 += b[i];
  }
  ans = sum1+sum2;
  cout << fixed << setprecision(10) << ans << endl;
  // cout << fixed << setprecision(10) << ((sum1+sum3)+sum2+sum4) << endl;
}