// 想定解
#include <bits/stdc++.h>
using namespace std;
void rc(int v,int mn,int mx){if(v<mn||mx<v){cerr<<"error"<<endl;exit(1);}}
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))

const int MAXN = 100;
const long long MAXF = 10000000000LL;

void f(const string &s, long long &ip, long long &fp){
    stringstream ss(s);
    string vf; char delim;
    ss >> ip >> delim >> vf;
    while(vf.size()<10) vf += "0";
    stringstream ssf(vf);
    ssf >> fp;
    if(s[0] == '-') fp=-fp;
    //cerr << ip << "." << fp << endl;
}

int main(){
    int N;
    cin >> N; rc(N, 0, MAXN);
    long long inte=0,frac=0;
    REP(i, N){
        string s; cin >> s;
        long long vi=0,vf=0;
        f(s, vi, vf);
        inte += vi; frac += vf;
    }
    while(frac < 0){inte--; frac += MAXF; }
    while(frac >= MAXF){inte++; frac -= MAXF; }

    if(inte < 0 && frac > 0){
        inte++; frac = MAXF - frac;
    }

    printf("%lld.%010lld\n", inte, frac);
    return 0;
}