#include <iostream>
#include <sstream>
using namespace std;
typedef long long ll;

const ll B = 1e10;

int main(){
    int N;
    cin >> N;
    
    ll inte = 0, frac = 0;
    for(int i=0;i<N;i++){
        string s, is, fs;
        cin >> s;
        
        int p = (int)s.find(".");
        if(p != -1){
            is = s.substr(0, p);
            fs = s.substr(p + 1);
        } else {
            is = s;
        }
        
        fs = fs + string(10 - fs.size(), '0');
        
        ll in = atoll(is.c_str());
        ll fr = atoll(fs.c_str());
        
        if(is[0] == '-')fr = -fr;
        
        inte += in;
        frac += fr;
    }
    
    while(frac < 0){
        --inte;
        frac += B;
    }
    
    while(frac >= B){
        ++inte;
        frac -= B;
    }
    
    if(inte < 0 && frac > 0){
        ++inte;
        frac = B - frac;
    }
    
    printf("%lld.%010lld\n", inte, frac);
    return 0;
}