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>
//#include <stdio.h>
#include<iostream>
#include<cstdio>
#include<bitset>
#include<algorithm>
#include<vector>
#include<list>
#include<queue>
#include<stack>
#include<string>
#include<string.h>
#include<cmath>
#include<utility>
#include<functional>
#include<map>
#include<set>
#include<cctype>
#include<fstream>
 
 
#define FOR(i, a, b) for( int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for( int i=(a);i>=(b);i--)
#define LFOR(i, a, b) for( long long int i=(a);i<=(b);i++)
#define LRFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979
#define MAXI 7500000
 
using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;
 
int dy[5] = { 0,0,1,-1,0 };
int dx[5] = { 1,-1,0,0,0 };
 
int main(void){

	while(1){
		string s,t;
		int miss=0;
		int spos=0;
		int tpos=0;
		int ssize,tsize;
		vector<string> ss(101),tt(101);
		int sspos=0;
		int ttpos=0;
		bool flag=false;

		cin>>s;
		if(s=="."){
			break;
		}
		cin>>t;
		ssize=s.size();
		tsize=t.size(); 

		flag=false;
		FOR(i,0,s.size()-1){
			if(s[i]=='"'){
				i++;
				
				while(s[i]!='"'){
					ss[sspos].push_back(s[i]);
					s.erase(s.begin()+i);
				}
				sspos++;
			}
		}

		FOR(i,0,t.size()-1){
			if(t[i]=='"'){
				i++;
				while(t[i]!='"'){
					tt[ttpos].push_back(t[i]);
					t.erase(t.begin()+i);
				}
				ttpos++;
			}
		}

		//cout<<s<<endl<<t<<endl;

		FOR(i,0,min(s.size()-1,t.size()-1)){
			if(s[i]!=t[i]){
				miss+=2;
			}
		}

		if(sspos!=ttpos){
			miss+=2;
		}else{
			FOR(i,0,sspos-1){
				if(ss[i]!=tt[i]){
					miss++;
				}
			}
		}

		if(miss==0){
			cout<<"IDENTICAL"<<endl;
		}else if(miss==1){
			cout<<"CLOSE"<<endl;
		}else{
			cout<<"DIFFERENT"<<endl;
		}

	}

}

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

int main(){
	while(1){
		string s1,s2;
		cin>>s1>>s2;
		
		if(s1=="."){
			break;
		}
		
		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('\"');
			t2.replace(d2e,1,"@");
		
			string u1=s1;
			string u2=s2;
			u1.replace(d1b+1,d1e-d1b-1,"");
			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 <string>
#include <vector>

using namespace std;

int main() {
	while (1) {
		string s, t, ans;
		vector<string> sl, tl;
		cin >> s;
		if (s == ".")break;
		cin >> t;
		if (s.size() < t.size()) {
			string a;
			a = s;
			s = t;
			t = a;
		}
		string a="";
		for (int i = 0; i < s.size(); i++) {
			if (s[i] != '"')a.push_back(s[i]);
			else {
				sl.push_back(a);
				a = "";
				i++;
				while (s[i] != '"') {
					a.push_back(s[i]);
					i++;
				}
				sl.push_back(a);
				a = "";
			}
		}
		if (a.size() > 0)sl.push_back(a);
		a = "";
		for (int i = 0; i < t.size(); i++) {
			if (t[i] != '"')a.push_back(t[i]);
			else {
				tl.push_back(a);
				a = "";
				i++;
				while (t[i] != '"') {
					a.push_back(t[i]);
					i++;
				}
				tl.push_back(a);
				a = "";
			}
		}
		if (a.size() > 0)tl.push_back(a);
		if (sl.size() != tl.size())ans = "DIFFERENT";
		else {
			int cnt = 0;
			for (int i = 0; i < sl.size(); i++) {
				if (i % 2 == 0 && sl[i] != tl[i]) {
					cnt = 2;
					break;
				}
				else if (i % 2 == 1 && sl[i] != tl[i]) {
					cnt++;
				}
			}
			if (cnt > 1)ans = "DIFFERENT";
			else if (cnt == 1) ans = "CLOSE";
			else ans = "IDENTICAL";
		}
		cout << ans << endl;
	}
	return 0;
}