Shell Programming and Scripting

#!/bin/csh
# This program will add integers
#
#
# add integer1 ..
#

# Check for argument
if ($#argv == 0 ) then
echo "usage: add integers"
exit 1
else
set input = $argv[*]
endif
#
set sum = 0
foreach var ( $input )
@sum = $sum + $input
end
#
echo "The sum total of the integers is $sum"
#
exit 0
#

Hi I am trying to make a program that adds all integers that are input.
ex. add 2 sum = 2
add 2 4 10 sum = 16

This is what i have for code but i keep getting the error "add: syntax error at line 18: `(' unexpected". If anyone could help me fix it i would appreciate it.