/* -*- coding: utf-8 -*-
 *
 * 81.cc: No.81 すべて足すだけの簡単なお仕事です。 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

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

  ll sumi = 0, sumf = 0;

  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;

    ll ii = 0, fi = 0;
    int sign = 1, pos = 0;

    if (pos < s.size() && s[pos] == '-')
      sign = -1, pos++;
    while (pos < s.size() && s[pos] != '.')
      ii = ii * 10 + s[pos++] - '0';
    if (pos < s.size() && s[pos] == '.') {
      pos++;
      int j = 0;
      while (pos < s.size())
	fi = fi * 10 + s[pos++] - '0', j++;
      while (j < 10) fi *= 10, j++;
    }
    //printf("%c%lld.%010lld\n", (sign < 0) ? '-' : ' ', ii, fi);

    if (sign > 0) sumi += ii, sumf += fi;
    else sumi -= ii, sumf -= fi;

    if (sumf < 0)
      sumf += 10000000000LL, sumi--;
    else if (sumf >= 10000000000LL)
      sumf -= 10000000000LL, sumi++;
  }

  if (sumi >= 0)
    printf("%lld.%010lld\n", sumi, sumf);
  else {
    //printf("sumi=%lld, sumf=%lld\n", sumi, sumf);
    if (sumf > 0) {
      sumf = 10000000000LL - sumf;
      sumi++;
    }
    printf("-%lld.%010lld\n", abs(sumi), sumf);
  }

  return 0;
}