View Compilation Error

0_0_21644990_7058.cpp: In function 'int main()':
0_0_21644990_7058.cpp:22:18: error: 'A' was not declared in this scope
             AB=a-A-ac,AC=c-C-bc,BC=b-B-ab,ABC=ab-AB;
                  ^
0_0_21644990_7058.cpp:23:37: error: 'AC' was not declared in this scope
             if(A<0||B<0||C<0||AB<0||AC<0||BC<0||ABC<0) continue;
                                     ^
0_0_21644990_7058.cpp:23:43: error: 'BC' was not declared in this scope
             if(A<0||B<0||C<0||AB<0||AC<0||BC<0||ABC<0) continue;
                                           ^
0_0_21644990_7058.cpp:23:49: error: 'ABC' was not declared in this scope
             if(A<0||B<0||C<0||AB<0||AC<0||BC<0||ABC<0) continue;
                                                 ^
0_0_21644990_7058.cpp:24:34: error: 'BC' was not declared in this scope
             ans=max(ans,A+B+C+AB+BC+AC+ABC );
                                  ^
0_0_21644990_7058.cpp:24:37: error: 'AC' was not declared in this scope
             ans=max(ans,A+B+C+AB+BC+AC+ABC );
                                     ^
0_0_21644990_7058.cpp:24:40: error: 'ABC' was not declared in this scope
             ans=max(ans,A+B+C+AB+BC+AC+ABC );
                                        ^