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;

vector<pair<string,bool>> parse(string s){
    bool isConstString = false;
    string tmp = "";
    vector<pair<string,bool>> res;
    for(int i = 0;i < s.size();i++){
        if(s[i] == '\"'){
            res.push_back(make_pair(tmp,isConstString));
            tmp = "";
            isConstString = !isConstString;
        }else{
            tmp += s[i];
        }
    }
    if(tmp.size())res.push_back(make_pair(tmp,isConstString));
    return res;
}

string solve(string s1,string s2){
    auto p1 = parse(s1);
    auto p2 = parse(s2);
    if(p1 == p2)return "IDENTICAL";
    if(p1.size() != p2.size())return "DIFFERENT";
    int cnt = 0;
    for(int i = 0;i < p1.size();i++){
        if(p1[i].second != p2[i].second)return "DIFFERENT";
        if(p1[i].first != p2[i].first){
            if(p1[i].second){
                cnt += 1;
            }else{
                return "DIFFERENT";
            }
        }
    }
    return (cnt > 1 ? "DIFFERENT" : "CLOSE");
}

int main(){
    string s1,s2;
    while(true){
        cin >> s1;
        if(s1 == "."){
            return 0;
        }
        cin >> s2;
        cout << solve(s1,s2) << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout.precision(12);
    cout.setf(ios_base::fixed, ios_base::floatfield);
    
    string s1, s2;
    while(true){
        cin >> s1;
        if(s1 == ".") break;
        cin >> s2;
        vector<string> st[2];
        string s_other[2] = {"", ""};
        string str = "";
        size_t addr = 0;
        while(addr < s1.size()){
            if(s1[addr] != '\"') s_other[0].push_back(s1[addr]);
            else{
                for(++addr;s1[addr]!='\"';++addr){
                    str.push_back(s1[addr]);
                }
                st[0].push_back(str);
                str = "";
                s_other[0].push_back('\"');
            }
            ++addr;
        }
        addr = 0;
        while(addr < s2.size()){
            if(s2[addr] != '\"') s_other[1].push_back(s2[addr]);
            else{
                for(++addr;s2[addr]!='\"';++addr){
                    str.push_back(s2[addr]);
                }
                st[1].push_back(str);
                str = "";
                s_other[1].push_back('\"');
            }
            ++addr;
        }
        //cerr << "-------------" << s_other[0] << "  " << s_other[1] << endl;
        if(s_other[0] == s_other[1]){
            int cnt = 0;
            for(int i=0;i<st[0].size();i++){
                if(st[0][i] != st[1][i]) cnt++;
                if(cnt > 1) break;
            }
            if(cnt == 0) printf("IDENTICAL\n");
            else if(cnt == 1) printf("CLOSE\n");
            else printf("DIFFERENT\n");
        }else{
            printf("DIFFERENT\n");
        }
    }
    
    return 0;
}

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

using namespace std;

int main(){

  string s1,s2;
  bool t = false;

  while(1){
	int cnt = 0;
	cin>>s1;

	if(s1==".")
	  break;

	cin>>s2;

	if(s1==s2){
	  cout<<"IDENTICAL"<<endl;
	  continue;
	}

	else{
	  int i=0;
	  int j=0;
	  t = false;
	  
	  while(1){

		if(s1[i]=='\0' &&  s2[j]=='\0')
		  break;
		
		if(s1[i]!=s2[j]){
		  cout<<"DIFFERENT"<<endl;
		  t = true;
		  break;
		}
		
		if(s1[i]=='\"' && s2[j]=='\"'){
		  i++;
		  j++;
		  
		  while(1){
			if(s1[i]=='\"' && s2[j]=='\"')
			  break;
			
			if(s1[i]!=s2[j]){
			  cnt++;
			  while(s1[i]!='\"')
				i++;
			  while(s2[j]!='\"')
				j++;
			  break;
			}
			i++;
			j++;
		  } 
		}
		  i++;
		  j++;
	  }
	  if(t == true)
		continue;
	}
	if(cnt == 1)
	  cout<<"CLOSE"<<endl;
	else
	  cout<<"DIFFERENT"<<endl;
  }
}

C++: #include <iostream>
#define LENGTH 201
using namespace std;
char str1[LENGTH];
char str2[LENGTH];

int main(){
    while(true){
        int cnt = 0;
        cin >> str1;
        if(str1[0] == '.')
            break;
        cin >> str2;
        for(int i = 0;i < LENGTH;i++){
            if(str1[i] != str2[i])
                cnt++;
        }
        if(cnt == 0)
            cout << "IDENTICAL" << endl;
        else if(cnt == 1)
            cout << "CLOSE" << endl;
        else
            cout << "DIFFERENT" << endl;
    }

    return 0;
}