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