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;

bool is_identical(string s1, string s2)
{
    return s1 == s2;
}

string s1, s2;
int main()
{
    while (true)
    {
        int cnt = 0;
        cin >> s1;
        if (s1[0] == '.')
            break;
        cin >> s2;
        int end1=0,end2 = 0;
        int start = 0;
        bool iden = false, close = false, diff = false;
        if (s1 == s2)
            iden = true;
        bool d = false;
        for (int i = 0; i < s1.size(); i++)
        {
            if (s1[i] == '"' && s2[i] == '"'){cnt = 1;d = !d;start = i;}
            else if (s1[i] != s2[i])
            {
                if (!d){diff = true;break;}
                else  {if(cnt == 1) {close = true;break;}}
            }
        }
        if(close == true){
        for(int i = start+1;i<max(s1.size(),s2.size());i++){
            if(end1!=0 && end2!=0) break;
            if(s1[i]=='"' && end1 == 0) end1 = i;
            if(s2[i]=='"' && end2 == 0) end2 = i;
        }
        }
        s1 = s1.substr(end1+1);
        s2 = s2.substr(end2+1);
        if(s1==s2) iden =true;
        else diff = true;
        
        if(iden && !close) cout << "IDENTICAL" << endl;
        else if(iden && close) cout << "CLOSE" << endl;
        else cout << "DIFFERENT" << endl;

    }

    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(s1[i]==s2[j]){
					i++; j++; continue;
			}
			if(!quo){
				close = -1;
				break;
			}else{
				close++;
				while(s1[i++]!='"'); i--;
				while(s2[j++]!='"'); j--;
			}
		}
		if(!(i==s1.size() && j == s2.size())) close = -1;
		cout << (close == 1 ? "CLOSE" : "DIFFERENT") << endl;
		
	}

	return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
	while(1){
		string s1;	
		cin>>s1;

		if(s1==".")
			break;

		string s2;
  		cin>>s2;	
		
		if(s1==s2){
			cout<<"IDENTICAL"<<endl;
		}
		
		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('\"');
			t1.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;
}

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

using namespace std;

int main(){
    while(true){
        string s,t;
        cin>>s;
        if(s==".")break;
        cin>>t;
        int si=0,ti=0;
        bool dq=false;
        int stat=0;//0:IDENTICAL 1:CLOSE 2:DIFFERENT
        while(si<s.size()&&ti<t.size()){
            if(dq){
                if(s[si]!=t[ti]){
                    ++stat;
                    while(s[si]!='"')++si;
                    while(t[ti]!='"')++ti;
                    dq=false;
                }
                if(s[si]=='"')dq=false;
            }
            else{
                if(s[si]!=t[ti]){
                    stat=2;
                    goto end;
                }
                else if(s[si]=='"')dq=true;
            }
            ++si;++ti;
        }
        if(si>=s.size()){
            if(stat==0||stat==1){
                if(ti<t.size())stat=2;
            }
        }
        else if(t[ti]>=t.size()){
            if(stat==0||stat==1){
                if(si<s.size())stat=2;
            }
        }
        end:;
        if(stat==0&&s.size()!=t.size())stat=2;
        switch(stat){
            case 0:
                cout<<"IDENTICAL"<<endl;
                break;
            case 1:
                cout<<"CLOSE"<<endl;
                break;
            default:
                cout<<"DIFFERENT"<<endl;
                break;
        }
    }
    return 0;
}