#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef pair<ll,ll> LL;

LL func (string s ){

	ll sign = 1LL;

	if (s[0] == '-' ) {
		sign = -1LL;
		s = s.substr (1 );
	} // end if

	rep (i, s.length() ) if (s[i] == '.' ) s[i] = ' ';

	stringstream ss (s );
	int integer = 0LL;
	string decimal = "";
	ss >> integer >> decimal;
	while (decimal.length() < 10 ){
		decimal += '0';
	} // end while

	stringstream tt (decimal );
	ll dec;
	tt >> dec;
	
	return LL (sign*integer, sign*dec );
}

string ll2s (ll m ){
	stringstream ss; 
	ss << m;
	string res; ss >> res; 
	while (res.length() < 10 ){
		res = '0' + res;
	} // end while
	
	return res;
}

int main()
{
	ios_base::sync_with_stdio(0);
	int N; cin >> N;
	vector<LL> num(N);
	rep (i, N ){
		string s; cin >> s;
		num[i] = func (s );
	} // end rep

	
	ll sumi = 0LL, sumd = 0LL;

	rep (i, N ){
		sumi += num[i].first;
		sumd += num[i].second;
//		cerr << num[i].first << '.' << num[i].second << endl;
	} // end rep
	sumi += sumd/(ll)1e10;
	string out2 = ll2s (abs((sumd + (ll)1e10 )%(ll)1e10 ) );
	cout << sumi << '.' <<  out2 << endl;

	return 0;
}