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 <vector>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cctype>
#include <cstring>
#include <utility>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;

bool check(string s1,string s2){
    int l=0,r=0;
    int cnt=0;
    while(l<s1.size() || r<s2.size())
    {
        //if(s1.size()==l || s2.size()==r)return false;
        if(s1[l]!=s2[r])return false;
        if(s1[l]=='"')
        {
            l++;
            string ss="";
            while(s1[l]!='"')
            {
                ss+=s1[l];
                l++;
            }
            r++;
            string ss2="";
            while(s2[r]!='"')
            {
                ss2+=s2[r];
                r++;
            }
            l++;
            r++;
            if(ss!=ss2)
            {
                cnt++;
            }
        }
        else
        {
            l++;
            r++;
        }
    }
    return (l==s1.size() && r==s2.size() && cnt<=1);
}

int main()
{
    while(1){
        string s1,s2;
        cin >> s1;
        if(s1==".")break;
        cin >> s2;
        if(s1==s2){
            printf("IDENTICAL\n");
        }else{
            printf("%s\n",check(s1,s2)?"CLOSE":"DIFFERENT");
        }
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<ll, ll>;
#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
template<typename T> void chmin(T &a, const T &b) { a = min(a, b); }
template<typename T> void chmax(T &a, const T &b) { a = max(a, b); }
struct FastIO {FastIO() { cin.tie(0); ios::sync_with_stdio(0); }}fastiofastio;
#ifdef DEBUG_ 
#include "../program_contest_library/memo/dump.hpp"
#else
#define dump(...)
#endif
const ll INF = 1LL<<60;

// sepで区切る
vector<string> split(const string &str, char sep) {
    vector<string> v;
    auto first = str.begin();
    while( first != str.end() ) {
        auto last = first;
        while( last != str.end() && *last != sep ) ++last;
        v.push_back(std::string(first, last));
        if( last != str.end() ) ++last;
        first = last;
    }
    return v;
}

int main(void) {
    while(1) {
        string s, t;
        cin >> s;
        if(s == ".") break;
        cin >> t;

        if(s == t) {
            cout << "IDENTICAL\n";
            continue;
        }

        auto vs = split(s, '\"'), vt = split(t, '\"');
        if(vs.size() != vt.size()) {
            cout << "DIFFERENT\n";
            continue;
        }
        
        ll cnt = 0;
        bool diff = false;
        const ll sz = vs.size();
        REP(i, sz) {
            if(i%2==0) {
                if(vs[i] != vt[i]) {
                    diff = true;
                    break;
                }
            } else if(vs[i] != vt[i]) {
                cnt++;
            }
        }
        if(cnt > 1) diff = true;

        if(diff) cout << "DIFFERENT\n";
        else cout << "CLOSE\n";
    }

    return 0;
}

C++: #include<iostream>

using namespace std;

int main(){

  char s1[200]={0};
  char s2[200]={0};
  char t1[200]={0};
  char t2[200]={0};
  char u1[200]={0};
  char u2[200]={0};

  int c=0,flag=0,j=0,k=0,l=0;

  cin>>s1>>s2;
 
  for(int i=0;i<200;i++){
    if(s1[i]=='"'){
      if(flag==0){
	flag=1;
	
      }else if(flag==1){
	flag=0;
	
      }
    }

    if(flag==1){
      t1[j]=s1[i];
      j++;    
    }

    if(flag==0){
      u1[l]=s1[i];
      l++;    
    }


  }
  j=0;
  l=0;
 for(int i=0;i<200;i++){

    if(s2[i]=='"'){
      if(flag==0){
	flag=1;
	
      }else if(flag==1){
	flag=0;
	
      }
    }

    if(flag==1){
      t2[j]=s2[i];
      j++;
    }

 if(flag==0){
      u2[l]=s2[i];
      l++;
    }

  }
 j=0;
 flag=0;

 /* cout<<t1<<endl;
 cout<<t2<<endl;
 cout<<u1<<endl;
 cout<<u2<<endl;*/

 //kyuukei~~~

   
  for(int i=0;i<150;i++){


    if(flag==1){
    if(t1[j]!=t2[k]){
      c++;
      flag=0;
    }

    if(t1[j]=='"' && t2[k]!='"'){
      j--;
    }
    if(t2[k]=='"' && t1[j]!='"'){
      k--;
    }

    j++;
    k++;

    }

   if(t1[j]=='"' && t2[k]=='"'){
     flag=1;

    }


  }

  for(int i=0;i<200;i++){
    if(u1[i]!=u2[i]){
      c=2;
    }
  }

    if(c==0){
      cout<<"IDENTICAL"<<endl;
    }else if(c==1){
      cout<<"CLOSE"<<endl;
    }else{
      cout<<"DIFFERENT"<<endl;
    }
  
return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main() {
	while (true) {
		string a, b;
		cin >> a;
		if (a[0] == ".") {
			break;
		}
		cin >> b;
		if (a == b) {
			cout << "IDENTICAL" << endl;
			continue;
		}
		int modea = 0, modeb = 0;
		int i = 0, j = 0, k = 0, c = 0;
		while(true){
			if (a[i+j] == '"') {
				switch(modea) {
					case 0:
						modea = 1;
						break;
					case 1:
						modea = 0;
						break;
				}
			}
			if (b[i+k] == '"') {
				switch(modeb) {
					case 0:
						modeb = 1;
						break;
					case 1:
						modeb = 0;
						break;
				}
			}
			if (modea == 1 and modeb==1) {
				if (a[i + j] != b[i + k]) {
					c++;
					continue;
				}
				j++;
				k++;
			}
			else if (modea == 1) {
				j++;
			}
			else if(modeb==1){
				k++;
			}
			else {
				if (a[i] != b[i]) {
					c = c + 2;
				}
				i++;
			}
		}
		if (c > 1) {
			cout << "DIFFERENT" << endl;
		}
		else {
			cout << "CLOSE" << endl;
		}
	}
}