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 <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i = 0; i < (n); i++)
using vi = vector<int>;
using vvi = vector<vi>;

signed main(){
  while(1){
      string s,t;
      cin>>s;
      if(s[0]=='.')break;
      cin>>t;
      int f=0;
      s+='d';
      t+='d';
      int n=s.length();
      int m=t.length();
      int i=0,j=0;
      //cerr<<"st"<<endl;
      while(1){
          if(i==n&&j==m){
              if(s[i-1]!=t[j-1]){
                cout<<"DIFFERENT"<<endl;
                break;
              }
              if(f==1){
                  cout<<"CLOSE"<<endl;
                  break;
              }
              cout<<"IDENTICAL"<<endl;
              break;
          }
          if(i>=n&&j>=m){
              cout<<"DIFFERENT"<<endl;
              break;
          }
          if(s[i]==t[j]&&s[i]!='\"'){
              i++;
              j++;
              continue;
          }else if(s[i]==t[j]&&s[i]=='\"'){
              int ii=i+1,jj=j+1,ff=1;
              for(;ii<n;ii++){
                  if(s[ii]=='\"')break;
              }
              for(;jj<m;jj++){
                  if(t[jj]=='\"')break;
              }
              if(ii==n||jj==m){
                  i++;
                  j++;
                  continue;
              }
              if(ii-i!=jj-j){
                  f+=1;
                  //cerr<<"cnt_f"<<endl;

              }else{
                for(int i2=i;i2<=ii;i2++){
                    //cerr<<s[i2]<<" "<<t[i2-i+j];
                    if(s[i2]!=t[i2-i+j]){
                        f+=1;
                        //cerr<<"diff_f"<<ii-i<<endl;
                        break;
                    }
                }     
              }
              if(f>=2){
                  cout<<"DIFFERENT"<<endl;
                  break;
              }
            

              i=ii;
              j=jj;
          }else if(s[i]!=t[j]){
              cout<<"DIFFERENT"<<endl;
                  break;
          }

          if(i==n&&j==m){
              if(s[i-1]!=t[j-1]){
                cout<<"DIFFERENT"<<endl;
                break;
              }
              if(f==1){
                  cout<<"CLOSE"<<endl;
                  break;
              }
              cout<<"IDENTICAL"<<endl;
              break;
          }
          if(i>=n&&j>=m){
              cout<<"DIFFERENT"<<endl;
              break;
          }
          i++;
          j++;
          
      }

  }
}

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

using namespace std;
typedef long long ll;

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.clear();
		}
		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 << "CLOSE" << endl;
		}
		else {
			cout << "DIFFERENT" << endl;
		}
	}
	
	return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<iomanip>
#include<stack>
#include<queue>
#include<string>
#include<set>
#include<map>
using namespace std;
#define rep(i,n) for(int i=0;(i)<(n);(i)++)
#define FOR(i,m,n) for(int i=(m);(i)<(n);(i)++)
typedef long long ll;

int main(){
    string s1,s2;
    while(cin >> s1 >> s2,s1!="."){
        if(s1==s2){
            cout << "IDENTICAL" << endl;
            continue;
        }
        vector<string> s1_strs,s2_strs;
        int ptr = 0;
        string s1_rest="",s2_rest="";
        while(ptr<s1.size()){
            if(s1[ptr]=='"'){
                s1_rest=s1_rest+" ";
                string push_str;
                while(s1[++ptr]!='"'){
                    push_str.push_back(s1[ptr]);
                }
                s1_strs.push_back(push_str);
            }else{
                s1_rest=s1_rest+s1[ptr];
            }
            ++ptr;
        }
        ptr=0;
        while(ptr<s2.size()){
            if(s2[ptr]=='"'){
                s2_rest=s2_rest+" ";
                string push_str;
                while(s2[++ptr]!='"'){
                    push_str.push_back(s2[ptr]);
                }
                s2_strs.push_back(push_str);
            }else{
                s2_rest=s2_rest+s2[ptr];
            }
            ++ptr;
        }
        int m = min(s1_strs.size(),s2_strs.size());
        int cnt=0;
        rep(i,m){
            if(s1_rest==s2_rest&&s1_strs[i]!=s2_strs[i])cnt++;
        }
        if(cnt==1)cout << "CLOSE" << endl;
        else cout << "DIFFERENT" << endl;
    }
    return 0;
}