#include <bits/stdc++.h>
using namespace std;
#define int long long
using ll=long long;
using vi=vector<int>;
using vl=vector<long long>;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
#define ITR(i,c) for(auto i=begin(c);i!=end(c);++i)
#define FORE(x,c) for(auto &x:c)
#define REPF(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define REP(i,n) REPF(i,0,n)
#define REPR(i,n) for(int i=(int)(n);i>=0;--i)
#define REPW(i,n) for(i=0;i<(int)(n);++i)
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)
#define SZ(c) ((int)c.size())
#define CONTAIN(c,x) (c.find(x)!=end(c))
#define OUTOFRANGE(y,x,h,w) (y<0||x<0||y>=h||x>=w)
#define dump(...)
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
#define INF (1001001001)
#define INFLL (1001001001001001001ll)
template<class T> ostream& operator << (ostream &os,const vector<T> &v) {
    ITR(i,v) os << *i << (i==end(v)-1 ? "" : " "); return os; }
template<class T> istream& operator >> (istream &is,vector<T> &v) {
    ITR(i,v) is >> * i; return is; }
template<class T> istream& operator >> (istream &is, pair<T,T> &p) {
        is >> p.first >> p.second; return is; }
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
//------------------------------------------------------------------------------
struct before_main_function {
    before_main_function() {
        #ifdef int
            #undef INF
            #define INF INFLL
            #define stoi stoll
        #endif
        cin.tie(0);ios::sync_with_stdio(false);
        cout<<setprecision(15)<<fixed;
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

int same(string a,string b) {
    vector<string> A,B,C,D;
    string tmp="";
    string tmp2="";
    int cnt=0;
    REP(i,SZ(a)) {
        if(a[i]=='"') {
            cnt++;
            if(cnt%2==0) {
                A.push_back(tmp);
                tmp="";
            }
            else {
                C.push_back(tmp2);
                tmp2="";
            }
        }
        else {
            if(cnt%2==0) {
                tmp2+=a[i];
            }
            else {
                tmp+=a[i];
            }
        }
    }
    C.push_back(tmp2);
    tmp=tmp2="";
    REP(i,SZ(b)) {
        if(b[i]=='"') {
            cnt++;
            if(cnt%2==0) {
                B.push_back(tmp);
                tmp="";
            }
            else {
                D.push_back(tmp2);
                tmp2="";
            }
        }
        else {
            if(cnt%2==0) {
                tmp2+=b[i];
            }
            else {
                tmp+=b[i];
            }
        }
    }
    D.push_back(tmp2);

    if(SZ(A)!=SZ(B)) return 0;
    if(SZ(C)!=SZ(D)) return 0;
    REP(i,SZ(C)) {
        if(C[i]!=D[i]) return 0;
    }

    cnt=0;
    REP(i,SZ(A)) {
        if(A[i]!=B[i]) cnt++;
    }
    if(cnt==0) {
        return 1;
    }
    else if(cnt==1) {
        return 2;
    }
    else {
        return 0;
    }
}
signed main() {
    while(1) {
        string s1,s2;
        cin>>s1;
        if(s1==".") break;
        cin>>s2;
        int res=same(s1,s2);
        if(res==0) cout<<"DIFFERENT"<<endl;
        else if(res==1) cout<<"IDENTICAL"<<endl;
        else cout<<"CLOSE"<<endl;
    }
    return 0;
}

Measured memory_bytes: 3140