Using Subroutine / Function in case statement

I have issue running functions under case statement

#!/bin/bash

single() {

Commands

}

multiple() {

Commands

}

until ["$input"="$3"] ; do

echo -e " \t \t M A I N - M E N U Perforce delete script \n"
echo -e "1. Remove a single user \n"
echo -e "2. Remove List of Users from file \n"
echo -e "3. Exit \n"
echo -n "Please enter option [1 - 3]"

read input

case "$input" in

1) single

2) multiple

3) echo "Bye $USER";
exit 1;;

*) echo "$input is a invalid option Please enter option between [1 - 3] only";
echo "Press [enter] key to continue. . .";
read enterKey;;

esac
done

I get :

./script.sh: line 68: syntax error near unexpected token `2)
./script.sh: line 68: `2) multiple'

I missed

1) single;;

2) multiple;;

Thanks,