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<algorithm>
#include<numeric>
#include<vector>
#include<set>
#include <math.h>
#include <string>
#define cinf(n,x,y) for(int i=0;i<(n);i++) cin >> x[i]>>y[i];
typedef long long int ll;
const ll INF =1LL << 62;
using namespace std;
int MAX_E=1000010;
ll dp[1000010];
void split(string s, vector<string> &v){
    v.clear();
    s +='"';
    string str="";
    for(int i=0;i<s.size();i++){
        if(s[i]=='"'){
            v.push_back(str);
            str="";
        }
        else{
            str+=s[i];
        }
    }
}
int main(){
    while(1){
        string s1,s2; cin >>s1;
        if(s1==".")break;
        cin >> s2;
        if(s1==s2){
            cout << "IDENTICAL"<< endl;
        }
        else{
            vector<string> v1,v2;
            split(s1,v1);
            split(s2,v2);
            if(v1.size()!=v2.size()){
                cout << "DIFFERENT" << endl;
            }
            else{
                bool a=false;
                int cnt=0;
                for(int i=0;i<v1.size();i++){
                    if(i%2==0){
                        if(v1[i]!=v2[i])a=true;
                    }
                    else{
                        if(v1[i]!=v2[i])cnt++;
                    }
                }
                if(a){
                    cout << "DIFFERENT" << endl;
                }
                else if(cnt>1){
                    cout << "DIFFERENT" << endl;
                }
                else{
                    cout << "CLOSE" << endl;
                }
            }
        }
    }
}

C++: #include <bits/stdc++.h>
using namespace std;

int main() {

    while(1){

        string s1,s2;

        cin >> s1;

        if(s1[0] == '.' && s1.size() == 1){
            break;
        }

        cin >> s2;

        string::iterator itr1 = s1.begin(),itr2 = s2.begin();

        bool firstdiff = false;

        bool is_into_quotation = false;

        string ans = "INCOLLECT";

        while(1){

            if(*itr1 == '"' && *itr2 == '"'){
                if(is_into_quotation){
                    is_into_quotation = false;
                }
                else{
                    is_into_quotation = true;
                }
            }

            if(*itr1 != *itr2){
                if(is_into_quotation && !firstdiff){

                    while(*itr1 != '"'){
                        itr1++;
                    }

                    while(*itr2 != '"'){
                        itr2++;
                    }

                    is_into_quotation = false;


                    firstdiff = true;
                }
                else{
                    ans = "DIFFERENT";
                    break;
                }
            }

            itr1++; itr2++;

            if(itr1 == s1.end() && itr2 == s2.end()){
                if(firstdiff){
                    ans = "CLOSE";
                }
                else{
                    ans = "IDENICAL";
                }
                break;
            }

        }

        cout << ans << 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(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;
					}else{
						isClose = true;
						while(s1[i + s1Offset] == '"'){
							s1Offset++;
						}
						while(s2[i + s2Offset] == '"'){
							s2Offset++;
						}
					}
				}else if(s1[i + s1Offset] == '"'){
					isInsideBlock = false;
				}
			}
			if(s1[i + s1Offset] == '\0' && s2[i + s1Offset] == '\0'){
				break;
			}
		}
		if(isDifferent){
			cout << "DIFFERENT" << endl;
		}else if(isClose){
			cout << "CLOSE" << endl;
		}else{
			cout << "IDENTICAL" << endl;
		}
	}
	return 0;
}