Language: C++

#include <iostream>
#include "string"

using namespace std;


int main(){
	while(1){
		string s1;
		cin>>s1;

		if(s1==".") break;

		string s2;
		cin>>s2;

		if(s1==s2){
			cout<<"IDENTIAL"<<endl;
			continue;
		}

		string t1=s1;
		string t2=s2;

		while (1) {
			size_t d1b=t1.find('??\"');
			if(d1b==string::npos) break;
			t1.replace(d1b,1,"@");

			size_t d1b=t1.find('??\"');
			t1.replace(d1e,1,"@");

			size_t d2b=t2.find('??\"');
			if(d2b==string::npos) break;
			t1.replace(d2b,1,"@");

			size_t d2b=t2.find('??\"');
			t1.replace(d2e,1,"@");

			string u1=s1;
			u1.replace(d1b+1,d1e-d1b-1,"");
			string u2=s2;
			u2.replace(d1b+2,d1e-d1b-2,"");

			if (u1==u2) {
				t1=u1;
				t2=u2;
				break;
			}
		}
		if(t1==t2) cout<<"CLOSE"<<endl;
		else cout<<"DEFFFENT"<<endl;
	}
	return 0;
}

Compiler output:
a.cc:26:44: warning: multi-character character constant [-Wmultichar]
   26 |                         size_t d1b=t1.find('??\"');
      |                                            ^~~~~~
a.cc:30:44: warning: multi-character character constant [-Wmultichar]
   30 |                         size_t d1b=t1.find('??\"');
      |                                            ^~~~~~
a.cc:33:44: warning: multi-character character constant [-Wmultichar]
   33 |                         size_t d2b=t2.find('??\"');
      |                                            ^~~~~~
a.cc:37:44: warning: multi-character character constant [-Wmultichar]
   37 |                         size_t d2b=t2.find('??\"');
      |                                            ^~~~~~
a.cc: In function 'int main()':
a.cc:26:44: warning: overflow in conversion from 'int' to 'char' changes value from '4144930' to '34' [-Woverflow]
   26 |                         size_t d1b=t1.find('??\"');
      |                                            ^~~~~~
a.cc:30:32: error: redeclaration of 'size_t d1b'
   30 |                         size_t d1b=t1.find('??\"');
      |                                ^~~
a.cc:26:32: note: 'size_t d1b' previously declared here
   26 |                         size_t d1b=t1.find('??\"');
      |                                ^~~
a.cc:30:44: warning: overflow in conversion from 'int' to 'char' changes value from '4144930' to '34' [-Woverflow]
   30 |                         size_t d1b=t1.find('??\"');
      |                                            ^~~~~~
a.cc:31:36: error: 'd1e' was not declared in this scope; did you mean 'd1b'?
   31 |                         t1.replace(d1e,1,"@");
      |                                    ^~~
      |                                    d1b
a.cc:33:44: warning: overflow in conversion from 'int' to 'char' changes value from '4144930' to '34' [-Woverflow]
   33 |                         size_t d2b=t2.find('??\"');
      |                                            ^~~~~~
a.cc:37:32: error: redeclaration of 'size_t d2b'
   37 |                         size_t d2b=t2.find('??\"');
      |                                ^~~
a.cc:33:32: note: 'size_t d2b' previously declared here
   33 |                         size_t d2b=t2.find('??\"');
      |                                ^~~
a.cc:37:44: warning: overflow in conversion from 'int' to 'char' changes value from '4144930' to '34' [-Woverflow]
   37 |                         size_t d2b=t2.find('??\"');
      |                                            ^~~~~~
a.cc:38:36: error: 'd2e' was not declared in this scope; did you mean 'd2b'?
   38 |                         t1.replace(d2e,1,"@");
      |                                    ^~~
      |                                    d2b