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>

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define RITR(x,c) for(__typeof(c.rbegin()) x=c.rbegin();x!=c.rend();x++)
#define setp(n) fixed << setprecision(n)

#define lf double
#define ll long long
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll,ll>
#define pi pair<int,int>

#define all(a) (a.begin()),(a.end())
#define rall(a) (a.rbegin()),(a.rend())
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define ins insert

using namespace std;

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	string s, t;
	while(cin>>s>>t, s!="."){
		if (s==t){
			cout << "IDENTICAL\n";
			continue;
		}
		bool isstr=false, cond;
		ll diff=0;
		ll spos=0, tpos=0;
		ll lsp = 0, ltp = 0;
		while(true){
			spos = s.find("\"", lsp);
			tpos = t.find("\"", ltp);
			if (spos==string::npos || tpos==string::npos){
				cond = s.substr(lsp) == t.substr(ltp);
			}else{
				cond = s.substr(lsp, spos-lsp) == t.substr(ltp, tpos-ltp);
			}
			if (!cond) (isstr) ? diff++ : diff+=2;
			if (spos==string::npos || tpos==string::npos) break;
			if (diff >= 2) break;
			isstr = !isstr;
			lsp = spos+1;
			ltp = tpos+1;
		}
		if (diff >= 2){
			cout << "DIFFERENT\n";
		}else{
			cout << "CLOSE\n";
		}
	}
	return 0;
}

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

using namespace std;

int main() {
    int cnt;
    string s1, s2, tmp;
    vector<string> sv1, sv2;

    while (cin >> s1) {
        if (s1 == ".") { break; }

        cin >> s2;

        sv1.clear(); sv2.clear();
        tmp = ""; cnt = 0;
        if (s1 == s2) { cout << "IDENTICAL" << endl; }
        else {
            for (int i = 0; i < s1.size()+1; i++) {
                if (s1[i] != '"' && i != s1.size()) { tmp += s1[i]; }
                else { sv1.push_back(tmp); tmp = ""; }
            }
            for (int i = 0; i < s2.size()+1; i++) {
                if (s2[i] != '"' && i != s2.size()) { tmp += s2[i]; }
                else { sv2.push_back(tmp); tmp = ""; }
            }
            if (sv1.size() != sv2.size()) { cnt += 2; }
            else {
                for (int i = 0; i < sv1.size(); i++) {
                    if (sv1[i] != sv2[i] && i % 2 == 1) { cnt++; }
                    else if (sv1[i] != sv2[i]) { cnt += 2; break; }
                }
            }
            cout << ((cnt == 1) ? "CLOSE" : "DEFFERENT") << 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._Equal(c2) == false) {
			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();
	}
}