compare variables in UNIX shell

I am trying to compare two variables in shell script, but it does not work although the code looks simple.
Basically the idea is to determine when an empty string is entered by a user and display a warning.
This is the code:
#!/bin/sh
echo "Enter value A:"
read  VALUEA
echo "$VALUEA"

echo "Enter VALUE B:"
read VALUEB
echo "$VALUEB"

X="5"
echo "$X"

if [ "$X$VALUEA"="$X" ];  then
 echo "You did not enter Value A.  Please try again $X$VALUEA and $X"
else
 echo "not empty"
fi

if [ "$X$VALUEB"="$X" ];  then
 echo "You did not enter ending date.  Please try again $X$VALUEB  and $X"
 else
 echo "not empty"
fi

exit
---------------------------
The problem is that regardless whether or not I enter a value A or B, it always displays:
You did not enter beginning date.  Please try again 5r and 5
You did not enter ending date.  Please try again 5  and 5

("r" is a value I entered for the value A.  I used that as a debugging display).

Please assist.