Go: package main

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

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 len(infos) == 0 {
			break
		}
		// 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 <vector>
#include <algorithm>
using namespace std;

int is_contain_keywords(string str,vector<string>& keywords) {
  int cnt = 0;
  vector<string>::iterator key_itr = keywords.begin();
  while(key_itr != keywords.end()) {
    if(str.find(*key_itr) != string::npos) {
      cnt++;
    }
    key_itr++;
  }
  return cnt;
}

string decode(string cipher) {
  vector<string> keywords;
  keywords.push_back("the");
  keywords.push_back("this");
  keywords.push_back("that");

  int remind_shift = -1;
  int max_cnt = 0;
  int str_len = cipher.length();
  for(int shift = 0;shift < 'z' - 'a';shift++) {
    string str = cipher;
    for(int i=0;i<str_len;i++) {
      if('a' < cipher[i] && cipher[i] < 'z') {
        str[i] = (cipher[i] - 'a' + shift) % ('z' - 'a') + 'a';
      }
    }
    if(is_contain_keywords(str,keywords) > max_cnt) {
      max_cnt = is_contain_keywords(str,keywords);
      remind_shift = shift;
    }
  }
  string ans = cipher;
  for(int i=0;i<str_len;i++) {
    if('a' < cipher[i] && cipher[i] < 'z') {
      ans[i] = (cipher[i] - 'a' + remind_shift) % ('z' - 'a') + 'a';
    }
  }
  return ans;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  string cipher;
  getline(cin,cipher);
  cout << decode(cipher) << endl;
}

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

const string alpha = "abcdefghijklmnopqrstuvwxyz";

int main()
{
  string s;
  while (getline(cin, s)) {

    for (int i = 0; i < 26; ++i) {
      for (unsigned int j = 0; j < s.size(); ++j) {
	if (isalpha(s[j]))
	  s[j] = alpha[(s[j]-'a'+1)%alpha.size()];
      }
      if (s.find("the", 0) != string::npos ||
	  s.find("this", 0) != string::npos ||
	  s.find("that", 0) != string::npos)
	break;
    }

    cout << s << endl;

  }
  return 0;
}

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

int main(){
	string s, strCopy;
	while (getline(cin, s)) {
		for(int j=0 ; j<26 ; j++){
			for(int i=0 ; i<s.size() ; i++){
				if(s[i]>='a' && s[i]<='z'){
					s[i] = (s[i]=='z')? 'a' : s[i] + 1;
				}
			}
			if( s.find( "the" ) != string::npos || s.find( "this" ) != string::npos || s.find( "that" ) != string::npos){
				cout << s << endl;
			}
		}
	}
	
	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <istream>

using namespace std;

int main(int argc, char **argv)
{
	char a[82], t;
	int n, p;
	
	while(cin.getline(a, 81, '\n')){
		n = strlen(a);
		for(int i = 0; i < n; i++){
			p = (int)(a[i++]-'t');
			if(a[i] == ' '){
				continue;
			}
			t = a[i++]-p;
			if(t < 'a'){
				t += 25;
			} else if(t > 'z'){
				t -= 25;
			}
			if(a[i] == ' '){
				continue;
			}
			if(t == 'h'){
				t = a[i++]-p;
				if(t < 'a'){
					t += 25;
				} else if(t > 'z'){
					t -= 25;
				}
				if(t == 'e' && a[i] == ' '){
					break;
				} else if(t == 'i'){
					t = a[i++]-p;
					if(t < 'a'){
						t += 25;
					} else if(t > 'z'){
						t -= 25;
					}
					if(t == 's' && a[i] == ' '){
						break;
					}
				} else if(t == 'a'){
					t = a[i++]-p;
					if(t < 'a'){
						t += 25;
					} else if(t > 'z'){
						t -= 25;
					}
					if(t == 't' && a[i] == ' '){
						break;
					}
				}
			}
		}
		
		for(int i = 0; i < n; i++){
			if(a[i] == ' ' || a[i] == '.' || a[i] == ','){
				printf("%c",a[i]);
			} else {
				t = a[i]-p;
				if(t < 'a'){
					t += 25;
				} else if(t > 'z'){
					t -= 25;
				}
				printf("%c",t);
			}
		}
		cout << endl;
	}
	
	return 0;
}

C++: #define _USE_MATH_DEFINES
#include <iostream>
#include <queue>
#include <vector>
#include <math.h>
#include <algorithm>
#include <iomanip>
#include <string>
#include <stack>
using namespace std;

int main(){
	string s;
	while(getline(cin, s)) {
		while (s.find("the") == string::npos && s.find("this") == string::npos && s.find("that") == string::npos) {
			for (int i = 0; i < s.length(); ++i) {
				if ('a' <= s[i] && s[i] <= 'z') {
					int c;
					c = (s[i] - 'a' + 1) % ('z' - 'a' + 1);
					s[i] = c + 'a';
				}
			}
		}
		cout << s << endl;
	}
	return 0;
}

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

bool isSmallAlphabet(char& ch) {
  /* a ~ z(ascii) : 97 ~ 122 */
  if('a' <= ch && ch <= 'z') return true;
  else return false;
}

bool isHit(string& str) {
  if(str.find("the") != str.npos) return true;
  else if(str.find("this") != str.npos) return true;
  else if(str.find("that") != str.npos) return true;
  else return false;
}

char shiftIndex(char ch) {
  if(isSmallAlphabet(ch)) {
    ch += 1;
    /* ???????????????????°?????????§???????????£??????*/
    if(!isSmallAlphabet(ch)) {
      ch -= 26;
    }
  }
  return ch;
}

/* ????????¶??????????§£??? */
void CaesarCipher(string str) {
  
  /* p??????????????¢??????????????????????????????????????? */
  for(int p = 0; p < 26; ++p) {

    transform(str.begin(), str.end(), str.begin(), shiftIndex);

    /* Find "the" or "this" or "that" */
    if(isHit(str)) {
      cout << str << endl;
    }
  }
}

int main() {
  string str;
  while(getline(cin, str)) {
    CaesarCipher(str);
  }
  return 0;
}