read count_of_number
if [[ "$count_of_number" -ge 1 && "$count_of_number" -le 500 ]]; then
    list_of_integers=0
    for number in $(seq 1 $count_of_number)
        do
            read numbers
            if [[ "$numbers" -ge -10000 && "$numbers" -le 10000 ]]; then
            list_of_integers=$(($numbers + $list_of_integers))
            else
                echo "the number: $numbers is out of the range (-10000 <= x <= 10000)"
                exit 1
            fi
        done
    average=$(echo "scale=4; $list_of_integers / $count_of_number" | bc -l | xargs printf "%.3f")
    echo $average
else
    echo "the count of number is out of the range (1 <= N <= 500)"
fi