#include<bits/stdc++.h>
#define ALL(v) std::begin(v),std::end(v)
using lint=long long;
using ld=long double;
int main(){
    std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);
    std::cout.setf(std::ios_base::fixed);std::cout.precision(10);
    lint n;std::cin>>n;
    lint a=0,b=0;
    std::string s;
    std::getline(std::cin,s);
    while(n--){
        std::getline(std::cin,s);
        lint x,y;
        if(auto found=std::find(ALL(s),'.');found!=s.end()){
            std::string t=std::string(s.begin(),found);
            std::string u=std::string(found+1,s.end());
            u.resize(10,'0');
            x=std::stoll(t);
            y=std::stoll(u);
            if(t.front()=='-')y=-y;
        }else{
            x=std::stoll(s);
            y=0;
        }
        a+=x;
        b+=y;
    }
    lint base=10'000'000'000;
    a+=b/base;
    b%=base;
    if(b<0){
        a--;
        b+=base;
    }
    bool flg=false;
    if(a<0&&b){
        a++;
        b=base-b;
        if(a==0)flg=true;
    }
    std::cout<<(flg?"-":"")<<a<<'.'<<std::setw(10)<<std::setfill('0')<<b<<'\n';
}