#include <iostream>
#include <iomanip>
#include <sstream>
#include <cmath>
#include <cstdio>
using namespace std;

#define D13 10000000000000

inline void stoll(const string &s, long long &x) {
    istringstream ss(s);
    ss >> x;
}

int main() {
    int N;
    string S;
    bool minus;
    long long sumint = 0, sumdec = 0, x;

    cin >> N;
    while (N--) {
        cin >> S;
        minus = S[0] == '-'? true: false;
        int dpos = S.find('.');
        if (dpos == string::npos) {
            stoll(S, x);
            sumint += x;
        }
        else {
            stoll(S.substr(0, dpos), x);
            sumint += x;
            string decpart = S.substr(dpos+1);
            stoll(decpart, x);
            x *= (long long)pow(10, 13-decpart.length());
            sumdec += minus? -x: x;
        }
    }
    sumint += sumdec / D13;
    if (sumdec < 0) {
        sumdec *= -1;
        sumdec %= D13;
        sumdec = D13 - sumdec;
    }
    else {
        sumdec %= D13;
    }
    sumdec = (sumdec + 500) / 1000;
    printf("%lld.%010lld\n", sumint, sumdec);


    return 0;
}