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>
using namespace std;
long long aa;bool bb;char ch;
long long scan()
{
	while(ch=getchar(),(ch<'0'||ch>'9')&&ch!='-');
	ch=='-'?(bb=1,aa=0):(bb=0,aa=ch-48);
	while(ch=getchar(),(ch>='0'&&ch<='9'))
		aa=aa*10+ch-48;
	return (bb?(-aa):(aa));
}
char s1[300],s2[300];
int len1,len2,flag,cnt;
int main()
{
	int i,j;
	while(1)
	{
		scanf("%s",s1+1);
		if(s1[1]=='.'&&s1[2]==0)
			break;
		scanf("%s",s2+1);
		len1=strlen(s1+1);
		len2=strlen(s2+1);
		if(len1==len2)
		{
			//cout<<"LEN"<<len1<<" "<<len2<<endl;
			for(i=1;i<=len1;++i)
				if(s1[i]!=s2[i])
					break;
			if(i>len1)
			{
				puts("IDENTICAL");
				continue;
			}
		}
		cnt=0;
		flag=0;
		{
			for(i=1,j=1;i<=len1&&j<=len2;++i,++j)
			{
				if(s1[i]==s2[j])
				{
					if(s1[i]=='"')
						++cnt;
					continue;
				}
				else
				{
					if(cnt%2==0)
					{
						flag=1;
						break;
					}
					else
					{
						if(flag==2)
						{
							flag=3;
							break;
						}
						flag=2;
						for(;i<=len1;++i)
							if(s1[i]=='"')
								break;
						for(;j<=len2;++j)
							if(s2[j]=='"')
								break;
						if(len1-i!=len2-j)
						{
							flag=4;
							break;
						}
					}
				}
			}
			if(flag==2)
				puts("CLOSE");
			else
				puts("DIFFERENT");
		}
	}
}

C++: #include<iostream>
#include<string>
#include<vector>

using namespace std;

void split(string &s, vector<string> &v) {
	s += '"';
	string buf = "";
	for (int i = 0; i < s.size(); i++) {
		if (s[i] == '"') {
			v.push_back(buf);
			buf = "";
		}
		else buf += s[i];
	}
}

int main() {

	while (1) {
		string S1, S2;
		cin >> S1;
		if (S1 == ".")break;
		cin >> S2;
		//すでに完全に一致ならば
		if (S1 == S2) {
			cout << "IDENTICAL" << endl;
			continue;
		}
		vector<string> v1, v2;
		split(S1, v1), split(S2, v2);

		if (v1.size() != v2.size()) {
			cout << "DIFFERENT" << endl;
			continue;
		}
		
		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;
		}
	}
	
	return 0;
}