#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('\"');	// t1 start position
			if (d1b == string::npos)
				break;
			t1.replace(d1b, 1, "@");

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

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

			size_t d2e = t2.find('\"'); // t2 end position
			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;
}
