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 <fstream>
#include <stdio.h>
#include <string.h>
#include <vector>

using namespace std;

int main(int argc, const char * argv[]) {
    // insert code here...
    
    
    /////////
    //write//
    /////////
    
    while(1){
        char s1[200]; cin >> s1;
        if(s1[0]=='.')break;
        char s2[200]; cin >> s2;
        vector<int> v;
        
        if(strcmp(s1,s2)==0)cout << "IDENTICAL" << endl;
        else{
            int now_s1 = 0;
            int now_s2 = 0;
            bool different =false;
            bool close = false;
            int close_cnt = 0;
            int s1_ten_cnt = 0;
            int s2_ten_cnt = 0;
            
            //s1,s2が"
            //s1only
            //s2only
            //以外
            
            for(int i=0; s1[i] != '\0'; i++){
                if(s1[i] == '\"'){
                    s1_ten_cnt++;
                }
            }
            for(int i=0; s2[i] != '\0'; i++){
                if(s2[i] == '\"'){
                    s2_ten_cnt++;
                }
            }
            
            for(int i=0; s1[now_s1] != '\0'; i++){
                if(s1_ten_cnt!=s2_ten_cnt){
                    different = true;
                    break;
                }
                if(s2[now_s2] == '\0' ){
                    break;
                }
                
                //close_cnt, different
                if(s1[now_s1] == '\"' && s2[now_s2] == '\"'){
                    while(1){
                        now_s1++;
                        now_s2++;
                        if(s1[now_s1] != s2[now_s2]){
                            close = true;
                        }
                        if(s1[now_s1] == '\"' && s2[now_s2] == '\"'){
                            break;
                        }else if(s1[now_s1] == '\"'){
                            bool tmp = false;
                            while(1){
                                now_s2++;
                                if(s2[now_s2]=='\"' || s2[now_s2]=='\0'){
                                    tmp =true;
                                    break;
                                }
                            }
                            if(tmp)break;
                        }else if(s2[now_s2] == '\"'){
                            bool tmp = false;
                            while(1){
                                now_s1++;
                                if(s1[now_s1]=='\"' || s1[now_s1]=='\0'){
                                    tmp =true;
                                    break;
                                }
                            }
                            if(tmp)break;
                        }
                    }
                    if(close){
                        close = false;
                        close_cnt++;
                    }
                    now_s1++;
                    now_s2++;
                }
                else if(s1[now_s1] == '\"'){
                    different = true;
                    break;
                }
                else if(s2[now_s2] == '\"'){
                    different = true;
                    break;
                }
                else {
                    if(s1[now_s1] != s2[now_s2]){
                        different = true;
                    }
                    now_s1++;
                    now_s2++;
                }
            }
            //output
            
            
            if(different)
                cout << "DIFFERENT" << endl;
            else
                if(close_cnt<=1){
                    cout << "CLOSE" << endl;
                }
                else{
                    cout << "DIFFERENT" << endl;
                }
        }//else
    }//while
    
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main(void){
	int n,m;
	while(true){
		string s1, s2;
		cin >> s1;
		if(s1 == ".")break;
		cin >> s2;
		if(s1 == s2){
			cout << "IDENTICAL" << endl;
			continue;
		}
		int close = 0;
		bool quo = false;
		int i = 0, j = 0;
		while(true){
			if(i==s1.size()||j==s2.size())break;
			if(s1[i] == '"' && s2[j] == '"'){
				quo = !quo;
				i++; j++;
				continue;
			}
			if(!quo){
				if(s1[i]!=s2[j]){
					close = 10; break;
				}else{
					i++; j++;
					continue;
				}
			}else{ 
				if(s1[i]!=s2[j]){
					close++;
					while(s1[++i]!='"');
					while(s2[++j]!='"');
				}else{
					i++; j++;
					continue;
				}
			}
		}
		cout << (close == 1 ? "CLOSE" : "DIFFERENT") << endl;
		
	}

	return 0;
}