#include <iostream>
#include <string>
using namespace std;

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

		if(s1==".")
			break;

		string s2;
		cin >> s2;

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

		string t1 = s1;
		string t2 = s2;

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

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

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

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

			string u1 = s1;
			u1.replace(d1b+1, d1e-d1b-1, "");
			string u2 = s2;
			u2.replace(d2b+1, d2e-d2b-1, "");

			if(u1==u2){
				t1 = u1;
				t2 = u2;
				break;
			}
		}

		if(t1==t2){
			cout << "CLOSE" << endl;
		}
		else{
			cout << "DIFFERENT" << endl;
		}
	}

	return 0;
}