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<vector>
#include<list>
#include<map>
#include<climits>
#include<set>
#include<deque>
#include<stack>
#include<bitset>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cctype>
#include<string>
#include<cstring>
#include<ctime>
#include<queue>
#include<random>
#include<cctype>
#include<fstream>




using namespace std;

typedef long long ll;
typedef long long LL;

typedef vector<int> VI;
typedef vector<VI> VVI;

int main() 
{
    //std::ofstream ofs("output.txt"); std::cout.rdbuf(ofs.rdbuf());

    while (true) {
        string s1, s2;
        cin >> s1 >> s2;

        if (s1.length() == 1 && s1 == ",") {
            break;
        }

        //完全に一致
        if (s1 == s2) {
            cout << "IDENTICAL" << endl;
            continue;
        }

        //""以外をチェック
        {
            vector<string> S1;
            vector<string> S2;

            string tmp = "";
            for (int i = 0; i < s1.size(); i++) {
                if (s1[i] == '"') {
                    while (true) {
                        i++;
                        if (s1[i] == '"') {
                            S1.push_back(tmp);
                            tmp = "";
                            break;
                        }
                    }
                }
                else {
                    tmp += s1[i];
                }
            }
            if (tmp.size() > 0) {
                S1.push_back(tmp);
            }

            tmp = "";
            for (int i = 0; i < s2.size(); i++) {
                if (s2[i] == '"') {
                    while (true) {
                        i++;
                        if (s2[i] == '"') {
                            S2.push_back(tmp);
                            tmp = "";
                            break;
                        }
                    }
                }
                else {
                    tmp += s2[i];
                }
            }
            if (tmp.size() > 0) {
                S2.push_back(tmp);
            }

            if (S1.size() != S2.size()) {
                cout << "DIFFERENT" << endl;
                continue;
            }
            else {
                bool good = true;
                for (int i = 0; i < S1.size(); i++) {
                    if (S1[i] != S2[i]) good = false;
                }
                if (!good) {
                    cout << "DIFFERENT" << endl;
                    continue;
                }
            }

        }

        //""内をチェック
        {
            vector<string> S1;
            vector<string> S2;

            for (int i = 0; i < s1.size(); i++) {
                string str = "";
                if (s1[i] == '"') {
                    while (true) {
                        i++;
                        if (s1[i] == '"') {
                            break;
                        }
                        str += s1[i];
                    }
                }
                S1.push_back(str);
            }
            for (int i = 0; i < s2.size(); i++) {
                string str = "";
                if (s2[i] == '"') {
                    while (true) {
                        i++;
                        if (s2[i] == '"') {
                            break;
                        }
                        str += s2[i];
                    }
                }
                S2.push_back(str);
            }

            if (S1.size() != S2.size()) {
                cout << "DIFFERENT" << endl;
            }
            else {
                int count = 0;
                for (int i = 0; i < S1.size(); i++) {
                    if (S1[i] != S2[i]) count++;
                }

                if (count > 1) {
                    cout << "DIFFERENT" << endl;
                }
                else {
                    cout << "CLOSE" << endl;
                }

            }

        }

    }

}

C++: #include<stdio.h>

int main()
{
	char s1[100][201],s2[100][201],a1[201],a2[201];
	int c,count,i,t,str,count_s1,count_s2;
	int br=0,judge=0,j,k;
	
	while(1)
	{
		j=0;
		k=0;
		count=0;
		count_s1=0;
		count_s2=0;
		
		while((c=getchar())!='\n')
		{
			if(c=='.')
			{
				br=1;
				break;
			}
			if(c=='"')
			{
				judge=1-judge;
				if(judge)
				{
					count_s1++;
					str=0;
				}
				else s1[count_s1-1][str]='\0';
			}
			if(judge)
			{
				s1[count_s1-1][str]=c;
				str++;
			}
			else
			{
				a1[j]=c;
				j++;
			}
		}
		a1[j]='\0';
		if(br) break;
		
		while((c=getchar())!='\n')
		{
			if(c=='"')
			{
				judge=1-judge;
				if(judge)
				{
					count_s2++;
					str=0;
				}
				else s2[count_s2-1][str]='\0';
			}
			if(judge)
			{
				s2[count_s2-1][str]=c;
				str++;
			}
			else
			{
				a2[k]=c;
				k++;
			}
		}
		a2[k]='\0';
		for(int i=0;;i++)
		{
			if(a1[i]=='\0' && a2[i]=='\0') break;
			if(a1[i]!=a2[i])
			{
				count=2;
				break;
			}
		}
		if(count_s1==count_s2 && count==0)
		{
			for(int i=0;i<count_s1;i++)
			{
				//printf("%s\n",s1[i]);
				//printf("%s\n\n",s2[i]);
				for(int t=0;;t++)
				{
					if(s1[i][t]=='\0'&&s2[i][t]=='\0') break;
					if(s1[i][t]!=s2[i][t])
					{
						count++;
						break;
					}
					
				}
			}
		}
		else count=2;
		if(count==0) printf("IDENTICAL\n");
		else if(count==1) printf("CLOSE\n");
		else printf("DIFFERENT\n");
	}
	return 0;
}