Go: package main

import (
	"bufio"
	"os"
	"strings"
	"fmt"
	"reflect"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func cipher(text string, direction int, int_shift int) string {
	shift, offset := rune(int_shift), rune(26)
	runes := []rune(text)
	for index, char := range runes {
		switch direction {
		case 1:
			if char >= 'a' && char <= 'z'-shift || char >= 'A' && char <= 'Z'-shift {
				char = char + shift
			} else if char > 'z'-shift && char <= 'z' || char > 'Z'-shift && char <= 'Z' {
				char = char + shift - offset
			}
		case -1:
			if char >= 'a'+shift && char <= 'z' || char >= 'A'+shift && char <= 'Z' {
				char = char - shift
			} else if char >= 'a' && char < 'a'+shift || char >= 'A' && char < 'A'+shift {
				char = char - shift + offset
			}
		}
		runes[index] = char
	}
	return string(runes)
}

func main() {
	for {
		infos := strings.Split(nextString(), " ")
		plain := make([]string, len(infos))
		if reflect.DeepEqual(infos, []string{}) {
			break
		}
		fmt.Println(infos)
		Decryption:
			for i := 0; i < 26; i++ {
				for j := range infos {
					plain[j] = cipher(infos[j], 1, i)
				}
				for j := range plain {
					if plain[j] == "this" || plain[j] == "that" || plain[j] == "the" {
						break Decryption
					}
				}
			}
			fmt.Println(strings.Join(plain, " "))
	}
}

C++: #include<iostream>
#include<map>
#include<string>
using namespace std;

typedef pair<string, string> P;

P next_word(string sentence) {
  if (sentence.empty()) return make_pair(string(""), string(""));
  if (sentence[0] == ' ' || sentence[0] == '.') {
    return make_pair("", sentence.substr(1));
  } else {
    P recur = next_word(sentence.substr(1));
    return make_pair(sentence[0] + recur.first, recur.second);
  }
}

bool acceptable(string sentence) {
  P p = next_word(sentence);

  while (! p.first.empty() ) {
    if (p.first == "this" || p.first == "the" || p.first == "that")
      return true;

    p = next_word(p.second);
  }
  return false;
}

char slip(char c) {
  if (c < 'a' || 'z' < c) return c;
  
  string alphabet = "abcdefghijklmnopqrstuvwxyza";
  int index = (int)(c - 'a');
  return alphabet[index + 1];
}

char slip(char c, int n) {
  for (int i = 0; i < n; i++)
    c = slip(c);

  return c;
}

string slip(string code, int n) {
  string val;
  for (int i = 0, len = code.length(); i < len; i++)
    val += slip(code[i], n);

  return val;
}

string decode(string code) {
  for (int i = 1; i < 27; i++) {
    string sentence = slip(code, i);
    if (acceptable(sentence))
      return sentence;
  }

  return "";
}

int main() {
  string code;
  while ( getline(cin, code) )
    cout << decode(code) << endl;
}

C++: #include<iostream>
#include<string>
#include<cstdio>
using namespace std;
int main() {
	string a = "";
	while (getline(cin, a)) {
		a += " ";
		string b = "";
		int z = 0, sum = 0;
		int k = a.length();
		for (int i = 0; i <k; i++) {
			if (a[i] == ' ' || a[i] == '.' || a[i] == ',') {
				b = a.substr(z, i - z);
				int t = (int)'t';
				string c = "";
				if (b.length() == 3 || b.length() == 4) {
					c = "";
					int w = t - (int)b[0];
					for (int i = 0; i < b.length(); i++) {
						int d = (char)((int)b[i] + w);
						if (d > 'z')
							d -= 26;
						else if (d < 'a')
							d += 26;
						c += (char)d;
					}
					if (c == "the" || c == "that" || c == "this") {
						sum = w;
						break;
					}
				}
				z = i + 1;
			}
		}
		string f = "";

		for (int i = 0; i < k-1; i++) {
			if (a[i] != ' ' && a[i] != '.' && a[i] != ',') {
				int g = (int)a[i] + sum;
				if (g >(int)'z')
					g -= 26;
				else if (g < (int)'a')
					g += 26;
				f += (char)g;
			}
			else {
				f += a[i];
			}
		}
		cout << f << endl;
	}
}

C++: #include <iostream>
#include <string>
using namespace std;

int main()
{
	string s;
	while (getline(cin, s))
	{
		string dec = s;
		while (true)
		{
			if (dec.find("the") != -1 || dec.find("this") != -1 || dec.find("that") != -1)
			{
				cout << dec << endl;
				break;
			}
			for (int i = 0; i < dec.size(); i++)
			{
				if ('a' <= dec[i] && dec[i] < 'z') dec[i]++;
				if (dec[i] == 'z') dec[i] = 'a';
			}
		}
	}

	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <math.h>
#include <vector>
#include <set>

using namespace std;
typedef long long LL;
static const double EPS = 1e-9;

#define FOR(i,k,n) for (int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n) 
void decode(vector<string> &words)
{
  int s=0;
  REP(i,words.size()){
    REP(j,26){
      REP(k,words[i].size()){
        if(words[i][k] >= 'a' && words[i][k] <= 'z' )
        words[i].replace(k, 1, 1,
              'a' + ( words[i][k] + 1 - 'a')%26 );
        
        if(words[i] == "the"||words[i] == "this" || words[i] == "that" ||
           words[i] == "the." || words[i] == "this." || words[i] == "that." )
          s = j;
      }
    }
  }
  REP(i,words.size())
    REP(j,words[i].size())
      if(words[i][j] >= 'a' && words[i][j] <= 'z' )
        words[i].replace(j, 1, 1, 'a' + (words[i][j] + s+1 - 'a')%26 );
}

int main(void){  
  vector<string> words;
  string bf;

  while(true){
    if(!(cin >> bf)) break;
    words.push_back(bf);
    int c = getchar();
    if(c=='\n'){
      decode(words);
      cout << words[0];
      FOR(i,1,words.size())
        cout << " " << words[i];
      cout << endl;
      words.clear();
    }
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int main(void){
        string a;

        while(getline(cin,a)){

            for(int i=0;i<26;i++){
                if(a.find("the")!=string::npos||a.find("this")!=string::npos||a.find("that")!=string::npos){
                    cout<<a<<endl;break;
                }
                else
                    for(int i=0;i<a.length();i++){
                        if(a[i]>='a'&&a[i]<='y')a[i]++;
                        else if(a[i]=='z')a[i]='a';
                    }
            }
        }
    return 0;
}

C++: #include<cstdio>
#include<cctype>
#include<cstring>
char str[1000000] = {0};
using namespace std;
int main(){
    int f = 0;
    while(scanf("%[^\n]",str)!=EOF){
        getchar();
        for(int i = 0;i <= 25; i++){
            for(int j = 0;j < strlen(str); j++){
                if(str[j] == ' ' || str[j] == '.')continue;
                str[j]++;
                if(str[j] > 122)str[j] = str[j]-26;
            }
            for(int j = 0;j < strlen(str); j++){
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'e')goto hoge;
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'i' && str[j+3] == 's')goto hoge;
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'a' && str[j+3] == 't')goto hoge;
            }
        }
        for(int i = 0;i < strlen(str); i++){
            if(str[i] == ' ' || str[i] == '.')continue;
            str[i] -= 25;
        }
        for(int i = 0;i <= 25; i++){
            for(int j = 0;j < strlen(str); j++){
                if(str[j] == ' ' || str[j] == '.')continue;
                str[j]--;
                if(str[j] < 97)str[j] = str[j]+25;
            }
            for(int j = 0;j < strlen(str); j++){
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'e')goto hoge;
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'i' && str[j+3] == 's')goto hoge;
                if(str[j] == 't' && str[j+1] == 'h' && str[j+2] == 'a' && str[j+3] == 't')goto hoge;
            }
        }
        hoge:
        printf("%s\n",str);
        memset(str,0,sizeof(str));
    }
    return 0;
}