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>
#include <vector>
using namespace std;

int main() {

  while(1) {
    string s1, s2;
    cin >> s1;
    if(s1 == ".") return 0;

    cin >>s2;

    string s1_cp = s1, s2_cp = s2;

    vector<int> cnt1(s1.size()),cnt2(s1.size());

    int j = 0;
    for(int i = 0; i < s1.size(); i++) {
      if(s1[i] == '\"') {
        cnt1[j] = i;
        j++;
      }
    }

    int k = 0;
    for(int i = 0; i < s2.size(); i++) {
      if(s2[i] == '\"') {
        cnt2[k] = i;
        k++;
      }
    }

    // cout << "log1" << endl;

    int diff = 0;
    if(j == k) {
      vector<string> cut1(j);
      vector<string> cut2(j);
      int era_sum1 = 0, era_sum2 = 0;

      // cout << "j " << j << endl;
      for(int i = 0; i < j-1; i+=2) {

        cut1[i] = s1.substr(cnt1[i], (cnt1[i+1] - cnt1[i])+1);
        s1_cp.erase(s1_cp.begin()+cnt1[i]-era_sum1, s1_cp.begin()+cnt1[i+1]+1-era_sum1);
        s1_cp.insert(s1_cp.begin()+cnt1[i]-era_sum1, '*');
        era_sum1 += (cnt1[i+1] - cnt1[i]+1)-1;

        cut2[i] = s2.substr(cnt2[i], (cnt2[i+1] - cnt2[i])+1);
        s2_cp.erase(s2_cp.begin()+cnt2[i]-era_sum2, s2_cp.begin()+cnt2[i+1]+1-era_sum2);
        s2_cp.insert(s2_cp.begin()+cnt2[i]-era_sum2, '*');
        era_sum2 += (cnt2[i+1] - cnt2[i]+1)-1;

        // cout <<"cut[i]" << endl;
        // cout << cut1[i] << " " << cut2[i] << endl;
        // cout << s1_cp << " " << s2_cp << endl;
      }

      // cout << "log2" << endl;

      for(int i = 0; i < cut1.size(); i++) if(cut1[i] != cut2[i]) diff++;
    }

    if(s1 == s2) {
      cout << "IDENTICAL" << endl;
    }else if(diff == 1 && s1_cp == s2_cp) {
      cout << "CLOSE" << endl;
    } else {
      cout << "DIFFERENT" << endl;
    }
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int main()
{
  while(1){
    int count;
    string n1;
    string n2;
    vector<string> n1s(0);
    vector<string> n2s(0);
    vector<string> n1ns(0);
    vector<string> n2ns(0);
    cin>>n1;
    if(n1==".") return 0;
    cin>>n2;
    int l1=n1.size();
    int l2=n2.size();
   
    int start=-1;
    int end=-2;
    for(int i=0;i<l1;i++){
      if(n1[i]=='"'){
	if(start==-1){
	  start=i+1;
	  string str=n1.substr(end+2,start-end-3);
	  n1ns.push_back(str);
	}else{
	  end=i-1;
	  string str=n1.substr(start,end-start+1);
	  n1s.push_back(str);
	  start=-1;
	}
      }
    }
    if(start==-1){
      string str=n1.substr(end+2,l1-(end+2));
      n1ns.push_back(str);
    }
    start=-1;
    end=-2;
    for(int i=0;i<l2;i++){
      if(n2[i]=='"'){
	if(start==-1){
	  start=i+1;
	  string str=n2.substr(end+2,start-end-3);
	  n2ns.push_back(str);
	}else{
	  end=i-1;
	  string str=n2.substr(start,end-start+1);
	  n2s.push_back(str);
	  start=-1;
	}
      }
    }
    if(start==-1){
      string str=n2.substr(end+2,l2-(end+2));
      n2ns.push_back(str);
    }
    int s1=n1s.size();
    int s2=n2s.size();
    int ma=s1-s2;
    if(ma==0){
      count=0;
      for(int i=0;i<s1;i++){
	if(n2s[i]!=n1s[i]) count++;
      }      
    }else{
      count=-1;
    }
    for(int i=0;i<n1ns.size();i++){
      if(n1ns[i]!=n2ns[i]) count=-1;
    }
    if(count==1){
      cout<<"CLOSE"<<endl;
    }else if(count==0){
      cout<<"IDENTICIAL"<<endl;
    } else{
      cout<<"DIFFERENT"<<endl;
    }
  }
  return 0;
}

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

int main(){
    string s;
    while(cin >> s, s != "."){
        string t;
        cin >> t;

        vector<string> v, w;
        v.push_back("");
        for(int i = 0 ; i < s.size() ; ++i){
            if(s[i] == '"'){
                v.push_back("");
            }else{
                v.back().push_back(s[i]);
            }
        }

        w.push_back("");
        for(int i = 0 ; i < t.size() ; ++i){
            if(t[i] == '"'){
                w.push_back("");
            }else{
                w.back().push_back(t[i]);
            }
        }

        string ans = "IDENTICAL";

        int cnt = 0;
        for(int i = 1 ; i < min(v.size(), w.size())  ; i += 2){
            if(v[i] != w[i]){
                ++cnt;
            }
        }

        if(cnt == 1){
            ans = "CLOSE";
        }else if(cnt > 1){
            ans = "DIFFERENT";
        }

        for(int i = 0 ; i < min(v.size(), w.size()) ; i += 2){
            if(v[i] != w[i]){
                ans = "DIFFERENT";
            }
        }

        if(v.size() != w.size()){
            ans = "DIFFERENT";
        }

        cout << ans << endl;
    }

    return 0;
}