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>
using namespace std;

int main()
{
	while (true) {
		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 (true) {
			size_t d1b = t1.find('\"');	// t1 start position
			if (d1b == string::npos)
				break;
			t1.replace(d1b, 1, "@");

			size_t d1e = t1.find('\"'); // t1 end position
			t1.replace(d1e, 1, "@");

			size_t d2b = t2.find('\"');	// t2 start position
			if (d2b == string::npos)
				break;
			t2.replace(d2b, 1, "@");

			size_t d2e = t2.find('\"'); // t2 end position
			t2.replace(d2e, 1, "@");

			string u1 = s1;
			u1.replace(d1b + 1, d1e - d1b - 1, "");
			string u2 = s2;
			u2.replace(d2b + 1, d2e - d2b - 1, "");

			if (u1 == u2) {
				t1 = u1;
				t2 = u2;
				break;
			}
		}

		if (t1 == t2) {
			cout << "CLOSE" << endl;
		}
		else {
			cout << "DIFFERENT" << endl;
		}
	}

	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" : "DIFFERENT") << endl;
        }
    }
    return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef pair<string, int> token;
int main() {
	string s1, s2;
	while (cin >> s1, s1 != ".") {
		cin >> s2;
		vector<token> v1, v2;
		int pos = 0;
		while (pos < s1.size()) {
			if (s1[pos] == '"') {
				pos++;
				string s = "";
				while (pos < s1.size() && s1[pos] != '"') {
					s.push_back(s1[pos]);
					pos++;
				}
				v1.emplace_back(s, 1);
				pos++;
			}
			else {
				string s = "";
				while (pos < s1.size() && s1[pos] != '"') {
					s.push_back(s1[pos]);
					pos++;
				}
				v1.emplace_back(s, 0);
			}
		}
		pos = 0;
		while (pos < s2.size()) {
			if (s2[pos] == '"') {
				pos++;
				string s = "";
				while (s2[pos] != '"') {
					s.push_back(s2[pos]);
					pos++;
				}
				v2.emplace_back(s, 1);
				pos++;
			}
			else {
				string s = "";
				while (pos < s2.size() && s2[pos] != '"') {
					s.push_back(s2[pos]);
					pos++;
				}
				v2.emplace_back(s, 0);
			}
		}
		if (v1.size() != v2.size()) {
			cout << "DIFFERENT" << endl;
			continue;
		}
		bool ok = 1;
		int cnt = 0;
		for (int i = 0; i < v1.size(); i++) {
			if (v1[i].second != v2[i].second) {
				ok = 0;
				break;
			}
			else if (v1[i].second == 1) {
				if (v1[i].first != v2[i].first) cnt++;
			}
			else {
				if (v1[i].first != v2[i].first) {
					ok = 0;
					break;
				}
			}
		}
		if (ok) {
			if (cnt == 0) cout << "IDENTICAL" << endl;
			else if (cnt == 1) cout << "CLOSE" << endl;
			else cout << "DIFFERENT" << endl;
		}
		else {
			cout << "DIFFERENT" << endl;
		}
	}
}

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<<"IDENTIAL"<<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 d1b=t1.find('??\"');
			t1.replace(d1e,1,"@");

			size_t d2b=t2.find('??\"');
			if(d2b==string::npos) break;
			t1.replace(d2b,1,"@");

			size_t d2b=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<<"DEFFFENT"<<endl;
	}
	return 0;
}