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 <string>
#define LENGTH 201
using namespace std;

int main(){
    while(true){
        string str1,str2;
        int cnt1c = 0,cnt2c = 0,cnt1s = 0,cnt2s = 0;
        cin >> str1;
        if(str1[0] == '.')
            break;
        cin >> str2;
        for(int i = 0;i < LENGTH;i++){
            if(str1[i] == '"')
                cnt1c++;
            if(str1[i] == ';')
                cnt1s++;
            if(str2[i] == '"')
                cnt2c++;
            if(str2[i] == ';')
                cnt2s++;
        }
        if(((cnt1c + cnt1s) - (cnt2c + cnt2s)) == 0){
            if(str1 == str2)
                cout << "IDENTICAL" << endl;
            else
                cout << "CLOSE" << endl;
        }
        else if(((cnt1c + cnt1s) - (cnt2c + cnt2s)) == 2)
            cout << "CLOSE" << endl;
        else
            cout << "DIFFERENT" << endl;
        
    }

    return 0;
}

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

using namespace std;

int main() {
	string s1, s2;
	while (cin >> s1) {
		if (s1 == ".") {
			break;
		}
		cin >> s2;

		if (s1 == s2) {
			cout << "IDENTICAL" << endl;
		}
		else {
			int s1c = 0;
			vector<string> s11;
			string subs1 = "";
			string kk = "";
			for (int i = 0; i < s1.size(); i++) {
				if (s1[i] == '"') {
					subs1 += '"';
					s1c++;
					if (s1c % 2 == 0) {
						s11.push_back('"' + kk + '"');
						kk = "";
					}
				}
				else if (s1c % 2 != 0) {
					kk += s1[i];
				}
				else {
					subs1 += s1[i];
				}
			}
			int s2c = 0;
			vector<string> s22;
			string subs2 = "";
			for (int i = 0; i < s2.size(); i++) {
				if (s2[i] == '"') {
					subs2 += '"';
					s2c++;
					if (s2c % 2 == 0) {
						s22.push_back('"' + kk + '"');
						kk = "";
					}
				}
				else if (s2c % 2 != 0) {
					kk += s2[i];
				}
				else {
					subs2 += s2[i];
				}
			}
			if (subs1 == subs2 && s11.size() == s22.size()) {
				int cc = 0;
				for (int i = 0; i < s11.size(); i++) {
					if (s11[i] != s22[i]) {
						cc++;
					}
				}
				if (cc == 1) {
					cout << "CLOSE" << endl;
				}
				else {
					cout << "DIFFERENT" << endl;
				}
			}
			else {
				cout << "DIFFERENT" << endl;
			}
		}

	}
	return 0;
}

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 == 1) {
				if (v1[i] != v2[i])cnt++;
			}
			else {
				if (v1[i] != v2[i]) {
					cout << "DIFFERENT" << endl;
					continue;
				}
			}
		}
		if (cnt > 1) {
			cout << "DIFFERENT" << endl;
		}
		else {
			cout << "CLOSE" << endl;
		}
	}
	
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
char s1[305], s2[305];
int len1, len2, tp1, tp2;
int main(){
    while(1){
       // puts("INN");
        scanf("%s",s1);
        if(s1[0]=='.')break;
        scanf("%s",s2);
        len1 = strlen(s1);
        len2 = strlen(s2);
        if(len1 == len2){
            for(int i = 0 ;i < len1 ;i++){
                if(s1[i] != s2[i]) goto BYY;
            }
        }else{
            goto BYY;
        }
        puts("IDENTICAL");
        continue;
        BYY:;
        tp1 = tp2 = 0;
        int gg = 0;
        while(tp1 != len1 || tp2 != len2){
//            printf("qwq %d %d\n",tp1,tp2);
            if(s1[tp1] != s2[tp2]){
                puts("DIFFERENT");
                goto BYEE;
            }
            if(s1[tp1] == '"' && s2[tp2]=='"'){
                int t1,t2;
                for(t1 = tp1+1;s1[t1]!= '"' ;t1++ ) ;
                for(t2 = tp2+1;s2[t2]!= '"' ;t2++ ) ;
                bool flag = false;
                if(t1-tp1 == t2-tp2){
                    for(int i = tp1 ; i <= t1 ; i++){
                        if(s1[tp1++]!=s2[tp2++]){
                            flag = true;
                            break;
                        }
                    }
                }else{
                    flag = true;
                }
                if(flag)gg++;
                tp1 = t1+1;
                tp2 = t2+1;
                if(gg>1){
                    puts("DIFFERENT");
                    goto BYEE;
                }
            }else{
                tp1++,tp2++;
            }


        }
        if(gg==1)puts("CLOSE");
        BYEE:;

    }
}