Write a shell script to display the digits which are in odd position in a given 5 digit number

Code for Write a shell script to display the digits which are in odd position in a given 5 digit number in Unix / Linux / Ubuntu

echo Enter a 5 digit number
read num
n=1
while [ $n -le 5 ]
do
a=`echo $num | cut -c $n`
echo $a 
n=`expr $n + 2`
done