import java.io.*;
import java.math.*;

class Main{

static final PrintWriter out=new PrintWriter(System.out);

public static void main(String[] args) throws IOException{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
String line="";
BigDecimal x=new BigDecimal("0.0");
while((line=br.readLine())!=null&&!line.isEmpty()){
int n=Integer.parseInt(line);
for(int i=0;i<n;i++){
BigDecimal y=new BigDecimal(line);
x=x.add(y);
}
x=x.setScale(10,RoundingMode.HALF_UP);
out.printf("%.10f",x);
out.flush();
}
}
}