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 <iostream>
#include <string>

using namespace std;

#define REP(i, n) for(int i=0; i<n; i++)

string s1, s2;
int main() {
    while(1) {
        cin >> s1;
        if (s1 == ".") break;
        cin >> s2;

        int error = 0;
        int ap = 0;
        int i=0, j=0;
        while (1) {
            if (i==s1.size()-1 || j==s2.size()-1) {
                if (s1[i]==s2[j] && i==s1.size()-1 && j==s2.size()-1) break;
                if (error==0 && ap%2==1) {
                    if (s1[s1.size()-1]!=s2[s2.size()-1]) {
                        error=2; break;
                    }
                    int apc = 0;
                    for(int k=i; k<s1.size(); k++) {
                        if (s1[k]=='"') apc++;
                    }
                    for(int k=j; k<s2.size(); k++) {
                        if (s2[k]=='"') apc++;
                    }
                    if (apc>2) {
                        error = 2; break;
                    } else {
                        error = 1; break;
                    }
                }
                error=2; break;
            }

            if (s1[i] == s2[j]) {
                if (s1[i]=='"') ap++;
                i++; j++; continue;
            }

            if (ap%2==0 || error==1) {
                error = 2; break;
            }
            
            error++;
            while(1) {
                if (s1[i]!='"') i++;
                if (s2[j]!='"') j++;
                if (s1[i]=='"' && s2[j]=='"') break;
            }
        }

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

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

int main()
{
    while(true){
        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(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;
}