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 <algorithm>
#include <vector>
#include <string>

using namespace std;

using lint = long long;
using ldouble = long double;

bool solve() {
    string S[2];
    cin >> S[0];
    if (S[0] == ".") return false;
    cin >> S[1];

    vector<string> div[2][2];
    for (int i = 0; i < 2; ++i) {
        S[i].push_back('\"');
        string tmp;
        int bra = 0;
        for (char c : S[i]) {
            if (c == '\"') {
                div[i][bra].push_back(tmp);
                bra = 1 - bra;
                tmp.clear();
            } else {
                tmp.push_back(c);
            }
        }
    }

    int diff = 0;
    for (int bra = 0; bra < 2; ++bra) {
        if (div[0][bra].size() != div[1][bra].size()) {
            cout << "DIFFERENT" << endl;
            return true;
        }

        for (int i = 0; i < div[0][bra].size(); ++i) {
            if (div[0][bra][i] != div[1][bra][i]) {
                diff += 2 - bra;
            }
        }
    }

    cout << (diff >= 2 ? "DIFFERENT"
                       : (diff == 1 ? "CLOSE" : "IDENTICAL"))
         << endl;
    return true;
}

int main() {
    while (solve()) {}
    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){
		cout<<i<<" "<<j<<endl;

		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){
			cout<<3<<endl;
			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<<"DEFFERENT"<<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;
}

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

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

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

int main(){
    for(string s1, s2;cin>>s1;){
        if(s1==".")break;
        cin>>s2;
        vector<string>v1, v2;
        split(s1, v1);
        split(s2, v2);
        int cnt = 0;
        if(v1.size() != v2.size()){
            cout<<"DIFFERENT"<<endl;
            continue;
        }
        int fail = 0;
        for(int i=0;i<v1.size();i++){
            if(i%2==0){
                if(v1[i] != v2[i])fail=1;
            }
            else{
                if(v1[i] != v2[i])cnt++;
            }
        }
        if(fail){
            cout<<"DIFFERENT"<<endl;
            continue;
        }
        if(cnt==0){
            cout<<"IDENTICAL"<<endl;
            continue;
        }
        if(cnt==1){
            cout<<"CLOSE"<<endl;
            continue;
        }
        cout<<"DIFFERENT"<<endl;
    }
    return 0;
}