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>
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;
}

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

C++: #include <iostream>
#include <string>
using namespace std;
int n,m,l;
string s1, s2;
void input() {
	cin >> s1;
	if (s1 == ".")return;
	cin >> s2;
}
void output() {
	cout << endl;
}
void prep() {
	n = s1.length();
	m = s2.length();
	s1 = s1 + "$";
	s2 = s2 + "$";
}
void solve() {
	int i = 0;
	int j = 0;
	int h = 1;
	int cnt = 0;
	while (i+j<m+n-1) {
		h = 1 - h;
		string c1 = "";
		string c2 = "";
		while (i < n) {
			c1=c1+s1[i];
			if (s1[i] == '"')break;
			i++;
		}
		i++;
		while (j < m) {
			c2=c2+s2[j];
			if (s2[j] == '"')break;
			j++;
		}
		j++;
		if (c1!=c2) {
			if (h == 0) {
				cout << "DIFFERENT";
				return;
			}
			cnt++ ;
			if (cnt == 2) {
				cout << "DIFFERENT";
				return;
			}
		}
	}
	if (cnt == 0)cout << "IDENTICAL"; else cout << "CLOSE";
}
int main() {
	while (true) {
		input();
		if (s1 == ".")break;
		prep();
		solve();
		output();
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
void _dbg(string){cout<<endl;}
template<class H,class... T> void _dbg(string s,H h,T... t){int l=s.find(',');cout<<s.substr(0,l)<<" = "<<h<<", ";_dbg(s.substr(l+1),t...);}
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 1120000000

vector<string> split(const string &str, char sep){
  vector<string> v;
  stringstream ss(str);
  string buffer;
  while( getline(ss, buffer, sep ) ) v.pb(buffer);
  if(str[str.size()-1] == sep) v.pb("");
  return v;
}

int solve(string &s, string &t){
  auto v = split(s, '"');
  auto u = split(t, '"');
  if(v.size()!=u.size()) return 0;
  int x = 0;
  rep(i,v.size()) if(v[i]!=u[i]){
    if(i%2==0) return 0;
    else x++;
  }
  if(x>1) return 0;
  if(x==1) return 1;
  else return 2;
}

int main(){
  string s,t;
  while(cin>>s, s!="."){
    cin>>t;
    int r = solve(s,t);
    if(r==0) cout << "DIFFERENT" << endl;
    else if(r==1) cout << "CLOSE" << endl;
    else cout << "IDENTICAL" << endl;
  }

  return 0;
}