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++: #include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e12;

vector<string> split(const string &s, char c = '\"'){
    vector<string> ret;
    stringstream ss(s);
    string t;
    while(getline(ss, t, c)){
        ret.push_back(t);
    }
    return ret;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    string s1, s2;
    while(1){
        cin >> s1;
        if(s1 == ".") break;
        cin >> s2;
        vector<string> ss1 = split(s1);
        vector<string> ss2 = split(s2);
        if(ss1.size() != ss2.size()){
            cout << "DIFFERENT" << endl;
            continue;
        }
        int cnt = 0;
        rep(i, 0, ss1.size()){
            if(i % 2 == 0){
                if(ss1[i] != ss2[i]) cnt += 2;
            }else{
                if(ss1[i] != ss2[i]) cnt++;
            }
        }
        if(cnt == 0){
            cout << "IDENTICAL" << endl;
        }else if(cnt == 1){
            cout << "CLOSE" << endl;
        }else{
            cout << "DIFFERENT" << endl;
        }
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f(i,x,n) for(int i=x;i<(int)(n);++i)
#define all(x) (x).begin(),(x).end()
const int mod=1000000007,MAX=200005,INF=1<<29;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    while(1){
        string S,T;
        cin>>S;
        if(S==".") break;
        cin>>T;
        
        if(S==T){
            cout<<"IDENTICAL"<<endl;
        }else{
            int a=0,b=0,c=0,d=0,e=0,f=0;
            for(int i=0;i<min(S.size(),T.size());i++){
                if(S[i]!=T[i]){
                    for(int j=0;j<i;j++){
                        if(S[j]=='"') a++;
                    }
                    for(int j=0;j<i;j++){
                        if(T[j]=='"') d++;
                    }
                    break;
                }
            }
            
            reverse(all(S));
            reverse(all(T));
            
            for(int i=0;i<min(S.size(),T.size());i++){
                if(S[i]!=T[i]){
                    for(int j=0;j<i;j++){
                        if(S[j]=='"') b++;
                    }
                    for(int j=0;j<i;j++){
                        if(T[j]=='"') e++;
                    }
                    break;
                }
            }
            
            reverse(all(S));
            reverse(all(T));
            
            for(int i=0;i<S.size();i++){
                if(S[i]=='"') c++;
            }
            for(int i=0;i<T.size();i++){
                if(T[i]=='"') f++;
            }
            //cout<<a<<" "<<b<<" "<<c;
            if(a%2==1&&b%2==1&&a+b==c&&d%2==1&&e%2==1&&d+e==f) cout<<"CLOSE"<<endl;
            else cout<<"DIFFERENT"<<endl;
        }
    }
    
}

C++: #include<iostream>
#include<algorithm>
#include<numeric>
#include<vector>
#include <string>
using namespace std;

void split(string s, vector<string> &v){
    v.clear();
    s +='"';
    string str="";
    for(int i=0;i<s.size();i++){
        if(s[i]=='"'){
            v.push_back(str);
            str="";
        }
        else{
            str+=s[i];
        }
    }
}
int main(){
    while(1){
        string s1,s2; cin >>s1;
        if(s1==".")break;
        cin >> s2;
        if(s1==s2){
            cout << "IDENTICAL"<< endl;
        }
        else{
            vector<string> v1,v2;
            split(s1,v1);
            split(s2,v2);
            if(v1.size()!=v2.size()){
                cout << "DIFFERENT" << endl;
            }
            else{
                bool a=false;
                int cnt=0;
                for(int i=0;i<v1.size();i++){
                    if(i%2==0){
                        if(v1[i]!=v2[i]){
                            cout << "DIFFERENT" << endl;
                            continue;
                        }
                    }
                    else{
                        if(v1[i]!=v2[i])cnt++;
                    }
                }
                if(cnt>1){
                    cout << "DIFFERENT" << endl;
                }
                else{
                    cout << "CLOSE" << endl;
                }
            }
        }
    }
}