import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        long sum=0;
        for(int i=0; i<N; i++){
            String S = sc.nextLine();
            sum+=inde(S);
        }
        long m=1000000000L;
        if(sum>0){
            long ans1=sum/m;
            long ans2=sum%m;
            System.out.println(ans1+"."+ans2+"0");
        }else{
            sum*=-1;
            long ans1=sum/m;
            long ans2=sum%m;
            System.out.println("-"+ans1+"."+ans2+"0");            
        }
    }
    static long inde(String S){
        long m=1000000000L;
        int t = S.indexOf(".");
        long x;
        if(t==-1){
            x=Long.parseLong(S)*m;
        }else{
            String S1=S.substring(0,t);
            String S2=S.substring(t+1);
            while(S2.length()<9){
                S2=S2+"0";
            }
            long x1=Long.parseLong(S1)*m;
            long x2=Long.parseLong(S2);
            if(S.contains("-")){
                x=x1-x2;
            }else{
                x=x1+x2;
            }
        }
        return x;
    }
}