#include <iostream>
using namespace std;
int ans[22];
int main(){
    int n;cin>>n;
    
    for(int i = 0; n > i; i++){
        string s;cin>>s;bool minus = false;
        if(s[0] == '-'){
            s = s.substr(1,s.size()-1);
            minus = true;
        }
        int dec = s.size();
        for(int j = 0; s.size() > j; j++){
            if(s[j] == '.'){
                dec = j;
                break;
            }
        }
        for(int j = 0; s.size() > j; j++){
            if(dec == j){
                continue;
            }
            if(dec < j){
                if(minus)ans[10+(j-dec)] -= s[j]-'0';
                else ans[10+(j-dec)] += s[j]-'0';
            }else{
                if(minus)ans[11+(j-dec)] -= s[j]-'0';
                else ans[11+(j-dec)] += s[j]-'0';
            }
        }
    }
    int pre = 0;
    for(int i = 20; 0 < i; i--){
        ans[i-1] += ans[i]/10;
        ans[i]%=10;
        if(ans[i] == 0 && pre == 0)pre = i+1;
        else if(ans[i] != 0){
            pre = 0;
        }
    }
    if(pre > 10)pre = 10;
    for(int i = pre; 20 >= i; i++){
        cout << ans[i];
        if(i == 10)cout << ".";
    }
    cout << endl;
        
}