package main

import (
	"bufio"
	"fmt"
	"io"
	"math/big"
	"os"
)

func solve(in io.Reader, out, err io.Writer) {
	num, sum, temp := 0, big.NewRat(0, 1), big.NewRat(1, 1)
        precision := 10
	fmt.Fscan(in, &num)
	for i := 0; i < num; i++ {
		fmt.Fscan(in, temp)
		sum.Add(sum, temp)
	}
	fmt.Fprintln(out, sum.FloatString(precision))

}

func main() {
	br := bufio.NewReaderSize(os.Stdin, int(1e7))
	solve(br, os.Stdout, os.Stderr)
}