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>
#include <algorithm>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <set>
#include <stdlib.h>
#include <string>
#include <utility>
#include <vector>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define loop(i, x, n) for (int i = (x); i < (n); i++)
#define all(v) (v).begin(), (v).end()
#define int long long
using namespace std;
const int MOD = 1e9 + 7;
const int INF = 1e10;
template<typename T> void cmax(T &a, T b) { a = max(a, b); }
template<typename T> void cmin(T &a, T b) { a = min(a, b); }
inline int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }

signed main() {
  string s, t;
  while (cin >> s >> t) {
    if (s == ".") return 0;
    if (s == t)
      cout << "IDENTICAL" << endl;
    else {
      vector<int> sq, tq;
      vector<string> S, T;
      string ns = "", nt = "";
      rep(i, s.size()) {
        if (s[i] == '"') {
          ns += " ";
          sq.push_back(i);
          int start = i++;
          while (s[i] != '"') i++;
          S.push_back(s.substr(start, i - start + 1));
          // cout << s.substr(start, i - start + 1) << endl;
        } else {
          ns += s[i];
        }
      }
      rep(i, t.size()) {
        if (t[i] == '"') {
          nt += " ";
          tq.push_back(i);
          int start = i++;
          while (t[i] != '"') i++;
          T.push_back(t.substr(start, i - start + 1));
        } else {
          nt += t[i];
        }
      }
      // rep(i, S.size()) cout << S[i] << ' ';
      // cout << endl;
      // rep(i, T.size()) cout << T[i] << ' ';
      // cout << endl;
      // cout << "ns=" << ' ' << ns << ' ' << "nt=" << ' ' << nt << endl;
      if (ns != nt) {
        cout << "DIFFERENT" << endl;
        goto at;
      }
      if (sq.size() != tq.size()) {
        cout << "DIFFERENT" << endl;
      } else {
        // rep(i, sq.size()) cout << sq[i] << ' ';
        // cout << endl;
        // rep(i, tq.size()) cout << tq[i] << ' ';
        // cout << endl;
        int cnt = 0;
        rep(i, S.size()) if (S[i] != T[i]) cnt++;
        // cout << cnt << endl;
        cout << (cnt == 1 ? "CLOSE" : "DIFFERENT") << endl;
      }
    at:;
    }
  }
  return 0;
}

C++: #include<iostream>
#include<cstring>
using namespace std;
char ca[2][205];

void print(int n){
	if(n<0)cout<<"DIFFERENT"<<endl;
	if(n==0)cout<<"CLOSE"<<endl;
	if(n>0)cout<<"IDENTICAL"<<endl;
}

bool check(int a,int b){
	if(a>=strlen(ca[0]) && b>=strlen(ca[1]))return true;
	if(a>=strlen(ca[0]) || b>=strlen(ca[1]))return false;
	if(ca[0][a]=='\"' && ca[1][b]=='\"')return true;
	if(ca[0][a]=='\"' || ca[1][b]=='\"')return false;
	if(ca[0][a]!=ca[1][b])return false;
	return check(a+1,b+1);
}

int main(){
	int n,m;
	int i,j,k;
	int a,b,c;
	int t[5];
	int flag;
	while(cin>>ca[0]){
		if(ca[0][0]=='.')break;
		cin>>ca[1];
		t[0]=0;t[1]=0;
		for(i=0;i<2;i++){
			for(j=0;j<strlen(ca[i]);j++){
				if(ca[i][j]=='\"')t[i]++;
			}
		}
		if(t[0]!=t[1]){
			print(-1);
			continue;
		}
		a=t[0]+1;
		t[0]=0,t[1]=0,flag=1;
		for(i=0;i<a;i++){
			if(!check(t[0],t[1])){
				if(i%2==0 || flag==0){
					flag=-1;
					break;
				}else flag=0;
			}
			for(j=0;j<2;j++){
				for(;t[j]<strlen(ca[j]) && ca[j][t[j]]!='\"';t[j]++);
				t[j]++;
			}
		}
		print(flag);
	}
}

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

using namespace std;

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

int main() {

	while (1) {
		string S1, S2;
		cin >> S1;
		if (S1 == ".")break;
		cin >> S2;
		//すでに完全に一致ならば
		if (S1 == S2) {
			cout << "IDENTICAL" << endl;
			continue;
		}
		vector<string> v1, v2;
		split(S1, v1), split(S2, v2);

		if (v1.size() != v2.size()) {
			cout << "DIFFERENT" << endl;
			continue;
		}
		
		int cnt = 0;
		for (int i = 0; i < v1.size(); i++) {
			if (i % 2 == 0) {
				if (v1[i] != v2[i]) {
					cout << "DIFFERENT" << endl;
					goto next;
				}
			}
			else {
				if (v1[i] != v2[i]) {
					cnt++;
				}
			}
		}
		if (cnt > 1) {
			cout << "DIFFERENT" << endl;
		}
		else {
			cout << "CLOSE" << endl;
		}
	next:;
	}
	
	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;
			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<<"DIFFERENT"<<endl;
	}
	return 0;
}