remove last letters in a word

Dear All, The data set is

Code:

* Example generated by -dataex-. To install: ssc install dataex
clear
input str10 var
"ACAC"
"BAC" 
"GAC" 
end

How can I remove the last AC from all words to obtain

Code:

* Example generated by -dataex-. To install: ssc install dataex
clear
input str10 var
"AC"
"B" 
"G" 
end

Thanks for your suggestions.