Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		s := io.NextLine()
		if s == "." {
			break
		}
		t := io.NextLine()
		if s == t {
			io.Println("IDENTICAL")
			continue
		}
		ss := strings.Split(s, "\"")
		tt := strings.Split(t, "\"")
		if len(ss) != len(tt) {
			io.Println("DIFFERENT")
			continue
		}
		cnt := 0
		for i := 0; i < len(ss); i++ {
			if i%2 == 0 {
				if ss[i] != tt[i] {
					cnt = -1
					break
				}
			} else {
				if ss[i] != tt[i] {
					cnt++
				}
			}
		}
		if cnt > 1 || cnt == -1 {
			io.Println("DIFFERENT")
		} else {
			io.Println("CLOSE")
		}
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := []interface{}{}
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: // ?????????.cpp : ??????????????? ??¢????????±????????§????????¨????????? ?????????????????????????????????
//

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

int main()
{
	
	while (true) {
		string s1;
		string s2;
		cin >> s1;
		if (s1 == ".")
			break;
		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;
}

C++: #include <bits/stdc++.h>
using namespace std;

//repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i, n) for(int i = 0; i < (int)(n); i++)

//container util
#define all(x) (x).begin(),(x).end()

//typedef
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<VLL> VVLL;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;


//conversion
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}


int main(){
  string s[2];
  while(true){
    cin >> s[0] ;
    if(s[0] == ".") break;
    cin >> s[1];
    if(s[0] == s[1]) cout << "IDENTICAL" << "\n";
    else{
      vector<string> ss;
      int cnt = 0;
      int prev = 0;
      int prev2 = 0;

      string firstSS = "";
      string lastSS = "";
      rep(i,s[0].size()){
        if(s[0][i] == '"'){
          cnt++;
          if(cnt % 2 == 1) prev = i;
          if(cnt == 1 && i != 0){
            firstSS = s[0].substr(0,i);
          }
          if(cnt > 1 && cnt % 2 == 0){
            ss.push_back(s[0].substr(prev,i-prev+1));
            prev2 = i;
          }
        }
      }
      if(prev2 != (int)s[0].size() - 1){
        lastSS = s[0].substr(prev2,(int)s[0].size()-prev2);
      }
      // cout << firstSS << ' ' << lastSS << "\n";
      // rep(i,ss.size()){
      //   cout << ss[i] << endl;

      vector<string> ss2;
      cnt = 0;
      prev = 0;
      prev2 = 0;
      string firstSS2 = "";
      string lastSS2 = "";

      rep(i,s[1].size()){
        if(s[1][i] == '"'){
          cnt++;
          if(cnt % 2 == 1) prev = i;
          if(cnt == 1 && i != 0){
            firstSS2 = s[1].substr(0,i);
          }
          if(cnt > 1 && cnt % 2 == 0){
            ss2.push_back(s[1].substr(prev,i-prev+1));
            prev2 = i;
          }
        }
      }
      if(prev2 != (int)s[1].size() - 1){
        lastSS2 = s[1].substr(prev2,(int)s[1].size()-prev2);
      }

      if(firstSS2 != firstSS || lastSS2 != lastSS || ss2.size() != ss.size()){
        cout << "DIFFERENT" << "\n";
      }else{
        int cnt = 0;
        rep(i,ss.size()){
          if(ss[i] == ss2[i]) continue;
          else cnt++;
        }
        if(cnt == 1) cout << "CLOSE" << "\n";
        else cout << "DIFFERENT" << "\n";
      }
    }
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
#include<cstdlib>
#include<map>
#include<iomanip>
#include<sstream>
#include<vector>
#include<stack>
#include<math.h>
#include<queue>
#include<complex>
#include<random>
#include<ctime>
#include<set>
using namespace std;


const long long int mod=1000000007;
const long long int INF=99999999999999999;


int main() {
	cout << fixed << setprecision(18);
	string s,t;
	//cin>>s>>t;
	while(s!="."){
		cin>>s;
		if(s=="."){return 0;}
		cin>>t;
		if(s==t){cout<<"IDENTICAL"<<endl;continue;}
		string stmp,ttmp;
		queue<string>sq,tq;
		long long int stime=0,ttime=0;
		for(int i=0;i<s.length();i++){
			if(s[i]=='"'){
				long long int id=i+1,len=0;
				i++;
				while(s[i]!='"'){
					i++;
					len++;
				}
				sq.push(s.substr(id,len));
				stmp.push_back('"');
				stmp.push_back('"');
			}else{
				stmp.push_back(s[i]);
			}
		}
		for(int i=0;i<t.length();i++){
			if(t[i]=='"'){
				long long int id=i+1,len=0;
				i++;
				while(t[i]!='"'){
					i++;
					len++;
				}
				tq.push(t.substr(id,len));
				ttmp.push_back('"');
				ttmp.push_back('"');
			}else{
				ttmp.push_back(t[i]);
			}
		}

		if(stmp!=ttmp){
			cout<<"DIFFERENT"<<endl;
			continue;
		}
			long long int cou=0;
		while(!sq.empty()){
			if(sq.front()!=tq.front()){cou++;}
			sq.pop();
			tq.pop();
		}
		if(cou>=2){cout<<"DIFFERENT"<<endl;}
		else{cout<<"CLOSE"<<endl;}
		
		
	}
}