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, n ,N) for(ll i = (n); i < (N); i++)
#define p(s) cout<<(s)<<endl
#define p2(a, b) cout<<(a)<<" "<<(b)<<endl
using namespace std;
typedef long long ll;
ll MOD = 1e9+7;
ll inf = 1e18;

string s1, s2;

vector<string> split_string(string s, char c){
	vector<string> s_vec;
	ll pre = 0;
	REP(i,0,s.size()){
		if(s[i] == c){
			s_vec.push_back(s.substr(pre, i-pre));
			pre = i+1;
		}
	}
	s_vec.push_back(s.substr(pre, s.size()-pre));
	return s_vec;
}
int main() {
	while (cin >> s1 && s1 != ".") {
		cin >> s2;
		ll no_match = 0;
		vector<string> s1_vec = split_string(s1, '"');
		vector<string> s2_vec = split_string(s2, '"');
		if(s1_vec.size() != s2_vec.size()){
			no_match = 2;
		}else{
			REP(i,0, s1_vec.size()){
				if(s1_vec[i] != s2_vec[i]){
					if(i%2) no_match++;
					else no_match = 2;
				}
			}
		}

		if(no_match == 0){
			p("IDENTICAL");
		}else if(no_match == 1){
			p("CLOSE");
		}else{
			p("DIFFERENT");
		}
	}

	return 0;
}

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

int main(){
    string s,t;
    while(cin >> s&&s!="."){
        cin >> t;
        vector<string> v1,u1,v2,u2;
        bool flag = 0;
        string tmp;
        for(int i=0;i<s.size();i++){
            if(s[i]=='"'&&!flag){
                v1.push_back(tmp);
                flag = 1;
                tmp.clear();
            }else if(s[i]=='"'&&flag){
                u1.push_back(tmp);
                flag = 0;
                tmp.clear();
            }else{
                tmp.push_back(s[i]);
            }
        }
        v1.push_back(tmp);
        string tmp2;
        flag = 0;
        for(int i=0;i<t.size();i++){
            if(t[i]=='"'&&!flag){
                v2.push_back(tmp2);
                flag = 1;
                tmp2.clear();
            }else if(t[i]=='"'&&flag){
                u2.push_back(tmp2);
                flag = 0;
                tmp2.clear();
            }else{
                tmp2.push_back(t[i]);
            }
        }
        v2.push_back(tmp2);
        
        if(v1.size()!=v2.size()||u1.size()!=u2.size()){
            cout << "DIFFERENT" << endl;
            continue;
        }
        flag =0;
        for(int i=0;i<v1.size();i++){
            if(v1[i]!=v2[i]){
                cout <<"DIFFERENT" << endl;
                flag = 1;
            }
        }
        if(flag)continue;
        int cnt = 0;
        for(int i=0;i<u1.size();i++){
            if(u1[i]!=u2[i]){
                cnt++;
            }
        }
        if(cnt==0){
            cout << "IDENTICAL" << endl;
        }else if(cnt==1){
            cout << "CLOSE" << endl;
        }else{
            cout << "DIFFERENT" << endl;
        }

        
    }
    return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
	while(1){
		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(1){
			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('\"');
			t1.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 <iostream>
#include <vector>
#include <string>
using namespace std;

vector<string> split(string s){
	vector<string> ret;
	string t="";
	for(int i=0;i<s.size();i++){
		if(s[i]=='"'){
			ret.push_back(t);	
			t="";
		}
		else t+=s[i];
	}
	ret.push_back(t);
	return ret;
}

int main (){
    string s,t;
	while(cin>>s && s!="."){
		cin>>t;
		if(s==t){
			cout<<"IDENTICAL"<<endl;
			continue;
		}
		vector<string> spl_s=split(s);
		vector<string> spl_t=split(t);
		if(spl_s.size()!=spl_t.size()){
			cout<<"DIFFERENT"<<endl;
			continue;
		}
		int count=0;
		for(int i=0;i<min(spl_s.size(),spl_t.size());i++){
			if(i%2==1){ //文字列定数
				if(spl_s[i]!=spl_t[i])count++;
			}else { //文字列定数でない
				if(spl_s[i]!=spl_t[i])count+=2;
			}
		}
		if(count==1)cout<<"CLOSE"<<endl;
		else cout<<"DIFFERENT"<<endl;
	}
}