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

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

static const double EPS = 1e-8;
static const double PI = 4.0 * atan(1.0);
static const double PI2 = 8.0 * atan(1.0);

#define REP(i,n)	for(int i=0;i<(int)n;++i)
#define ALL(c)		(c).begin(),(c).end()
#define CLEAR(v)	memset(v,0,sizeof(v))
#define MP(a,b)		make_pair((a),(b))
#define ABS(a)		((a)>0?(a):-(a))
#define FOR(i,s,n)	for(int i=s;i<(int)n;++i)

int main(int argc, char **argv) {
	int N;
	cin >> N;
	ll sum1 = 0, sum2 = 0;
	REP(i, N) {
		string A;
		cin >> A;
		ll v = 0;
		int j = 0;
		int sign = 1;
		if (A[0] == '-') {
			sign = -1;
			++j;
		}
		for (; j < A.length() && A[j] != '.'; ++j) {
			v *= 10;
			v += A[j] - '0';
		}
		sum1 += sign * v;
		v = 0;
		REP(k, 10) {
			v *= 10;
			v += (j + 1 + k < A.size()) ? A[j + 1 + k] - '0' : 0;
		}
		sum2 += sign * v;
	}
	sum1 += sum2 / 10000000000;
	sum2 %= 10000000000;
	cout << sum1 << "." << setw(10) << setfill('0') << sum2 << endl;
	return 0;
}