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;
using lint = long long;
template<class T = int> using V = vector<T>;
template<class T = int> using VV = V< V<T> >;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  while (true) {
    string s; cin >> s;
    if (s == ".") break;
    string t; cin >> t;
    auto fn = [](const string& s) -> pair< string, V<string> > {
      bool b = false;
      pair< string, V<string> > res;
      string curr;
      for (char c : s) {
        if (c == '"') {
          if (b) {
            res.first += '#';
            res.second.push_back(curr);
            curr = "";
          }
          b ^= true;
        } else {
          (b ? curr : res.first) += c;
        }
      }
      return res;
    };
    auto a = fn(s), b = fn(t);
    if (a == b) cout << "IDENTICAL\n";
    else if (a.first != b.first) cout << "DIFFERENT\n";
    else {
      bool f = true;
      if (a.second.size() != b.second.size()) f = false;
      int c = 0;
      if (f) {
        for (int i = 0; i < (int)a.second.size(); ++i) {
          c += a.second[i] != b.second[i];
        }
        if (c != 1) f = false;
      }
      cout << (f ? "CLOSE\n" : "DIFFERENT\n");
    }
  }
}

C++: #include <iostream>
#include <string>
#include <vector>

using namespace std;

string s, t;
string S, T;
vector<string> vecs, vect;

int main(void)
{
	while(1){
		cin >> s;
		if(s == ".") break;
		cin >> t;
		
		S = "", T = "";
		vecs.clear(), vect.clear();
		{
			bool in = false;
			string buf;
			for(int i = 0; i < s.size(); i++){ 
				if(s[i] == '\"'){
					S += s[i];
					if(in){
						vecs.push_back(buf);
						buf = "";
						in = false;
					}
					else in = true;
				}
				else if(in){
					buf += s[i];
				}
				else S += s[i];
			}
		}
		{
			bool in = false;
			string buf;
			for(int i = 0; i < t.size(); i++){ 
				if(t[i] == '\"'){
					T += t[i];
					if(in){
						vect.push_back(buf);
						buf = "";
						in = false;
					}
					else in = true;
				}
				else if(in){
					buf += t[i];
				}
				else T += t[i];
			}
		}
		
		if(S != T){
			cout << "DIFFERENT" << endl;
			continue;
		}
		if(vecs.size() != vect.size()){
			cout << "DIFFERENT" << endl;
			continue;
		}
		int cnt = 0;
		for(int i = 0; i < vecs.size(); i++){
			if(vecs[i] != vect[i]) cnt++;
		}
		if(cnt == 0){
			cout << "IDENTICAL" << endl;
		}
		if(cnt == 1){
			cout << "CLOSE" << endl;
		}
		if(cnt >= 2){
			cout << "DIFFERENT" << endl;
		}
	}
	
	return 0;
}

C++: #include <iostream>
#include <string>
#include <sstream>

int main(){
    int cnt;
    std::string str1;
    std::string str2;
    std::string tmp1;
    std::string tmp2;
    while(true){
        std::cin >> str1;
        if(str1=="."){
            break;
        }
        std::cin >> str2;
        cnt = 0;
        std::istringstream iss1(str1);
        std::istringstream iss2(str2);
        while(std::getline(iss1,tmp1,';') && std::getline(iss2,tmp2,';')){
            if(tmp1 != tmp2){
                cnt++;
            }
        }
        if(cnt==0){
            std::cout << "IDENTICAL\n";
        }else if(cnt==1){
            std::cout << "CLOSE\n";
        }else{
            std::cout << "DIFFERENT\n";
        }
    }
}

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<<"IDENTIAL"<<endl;
			continue;
		}

		string t1=s1;
		string t2=s2;

		while (1) {
			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;
			t1.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(d1b+2,d1e-d1b-2,"");

			if (u1==u2) {
				t1=u1;
				t2=u2;
				break;
			}
		}
		if(t1==t2) cout<<"CLOSE"<<endl;
		else cout<<"DEFFFENT"<<endl;
	}
	return 0;
}

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

int main(){
	while(true){
		char s1[200], s2[200];
		cin >> s1;
		if(s1[0] == '.' && s1[1] == '\0'){
			break;
		}
		cin >> s2;
		bool isClose = false, isDifferent = false;
		bool isInsideBlock = false;
		int s1Offset = 0, s2Offset = 0;
		for(int i = 0; i < 200; i++){
			if(s1[i + s1Offset] == '\0' && s2[i + s1Offset] == '\0'){
				break;
			}
			if(!isInsideBlock){
				if(s1[i + s1Offset] != s2[i + s2Offset]){
					isDifferent = true;
					break;
				}else if(s1[i + s1Offset] == '"'){
					isInsideBlock = true;
				}
			}else{
				if(s1[i + s1Offset] != s2[i + s2Offset]){
					if(isClose){
						isDifferent = true;
						break;
					}else{
						isClose = true;
						while(s1[i + s1Offset] != '"'){
							s1Offset++;
						}
						while(s2[i + s2Offset] != '"'){
							s2Offset++;
						}
						isInsideBlock = false;
					}
				}else if(s1[i + s1Offset] == '"'){
					isInsideBlock = false;
				}
			}
			
		}
		
		if(isDifferent){
			cout << "DIFFERENT" << endl;
		}else if(isClose){
			cout << "CLOSE" << endl;
		}else{
			cout << "IDENTICAL" << endl;
		}
	}
	return 0;
}