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 <string>

using namespace std;

int main()
{
  string stro, str;
  while(getline(cin, stro)){
    for(int i = 0; i < 26; i++){
      str = stro;
      for(int j = 0; j < stro.length(); j++){
	if(str[j] != ' ' && str[j] != '.' && str[j] != '\n')
	  if(str[j] + i > 'z')
	    str[j] += i - 26;
	  else
	    str[j] += i;
      }
      unsigned f_the = str.find("the", 0);
      unsigned f_this = str.find("this", 0);
      unsigned f_that = str.find("that", 0);
      str.append("x");
      if((f_the != string::npos && f_the == 0 && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\n')) || (f_this != string::npos && f_this == 0 && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\n')) || (f_that != string::npos && f_that == 0 && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\n')))
	cout << str << endl;
      else if((f_the != string::npos && (str[f_the - 1] == ' ' || str[f_the - 1] == '.' || str[f_the - 1] == '\n') && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\n')) || (f_this != string::npos && (str[f_this - 1] == ' ' || str[f_this - 1] == '.' || str[f_this - 1] == '\n') && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\n')) || (f_that != string::npos && (str[f_that - 1] == ' ' || str[f_that - 1] == '.' || str[f_that - 1] == '\n') && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\n')))
	cout << str << endl;	 
    }
  }
}

C++: 	if('A'<= p && p <='Z'){
		p-='A';
		if(n<0) n+=26;
		p+=n;
		p%=26;
		p+='A';
		return p;
	}
	else if('a'<= p && p <='z'){
		p-='a';
		if(n<0) n+=26;
		p+=n;
		p%=26;
		p+='a';
		return p;
	}
	else return p;
}
/*
int checkch(char p){
	if('A'<= p && p <='Z') return 2;
	else if('a'<= p && p <='z') return 1;
	else return 0;
}
*/

int main(){

	int	i, j, n;
	char in[1000], *p, *tp;
	p= in;

	scanf("%[^\n]", in);
	for(n=0; 16<=in[n] && in[n]<=126; n++);
//		printf("%d\n", --n);

	while(1){
		tp=p;
		for(i=0; *(p++)!=' ';	i++);
		if(i==3||i==4){

			j=*tp-'t'; if(*(tp+1)=='h'+j) break;
			j=*tp-'T'; if(*(tp+1)=='h'+j){
			j+='a'-'A';
			break;
			}
		}
	}
	for(i=0; i<n; i++)	in[i]=shiftch(in[i],-j);

	printf("%s\n",in);

	return 0;
}

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


int main(void){
	string org;
	
	while(getline(cin,org)){

	for(int i=0; i<26; i++){
		for(int j=0; j<org.size(); j++){
			if( org[j] == '.' || org[j] == ' ' ) {}
			else {
				org[j]++;
				if( org[j] > 'z' )
					org[j] -= 26;
			}
		}
		string::size_type pos;
		pos = org.find("the");
		if( pos != string::npos ){
			cout << org << endl;
		}
		else{
			pos = org.find("this");
			if( pos != string::npos ){
				cout << org << endl;
			}
			else{
			pos = org.find("that");
			if( pos != string::npos ){
				cout << org << endl;
			}
			}
		}
	}
	}
	return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>

using namespace std;
typedef long long ll;

int main(){
    int in;
    char S[1000];
    
    for(int i=0;;i++){
        
        in = getchar();
        
        if(in==EOF){
            S[i]='\0';
            break;
        }else{
            S[i]=(char)in;
        }
    }
    
    for(int k=0;;k++){
        
        bool f = false;
        
        for(int i=0;;i++){
            if('a'<=S[i] && S[i]<='y'){
                S[i]++;
            }else if(S[i]=='z'){
                S[i]='a';
            }
            
            if(i>=2){
                if(S[i-2]=='t' && S[i-1]=='h' && S[i]=='e')
                    f=true;
            }
            if(i>=3){
                if(S[i-3]=='t' && S[i-2]=='h')
                    if((S[i-1]=='i' && S[i-0]=='s') || (S[i-1]=='a' && S[i-0]=='t'))
                        f=true;
            }
            
            if(S[i]=='\0') break;
        }
        
        if(f) break;
    }
    
    for(int i=0;S[i]!='\0';i++)
        printf("%c",S[i]);
    
    return 0;
}

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

bool decision(string input){
	for(int i = 0; i < input.size()-3; i++){
		if((input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'e') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'i' && input[i+3] == 's') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'a' && input[i+3] == 't')){
			return true;
		}
	}
	return false;

}

int main(){
	string abc = "abcdefghijklmnopqrstuvwxyz";
	string input;
	getline(cin, input);

	while(1){
		for(int i = 0; i < input.size(); i++){
			for(int j = 0; j < abc.size(); j++){
				if(input[i] == abc[j]){
					if(j != 0){
						input[i] = abc[j-1];
					}else{
						input[i] = abc[abc.size()-1];
					}
				}
			}
		}
		if(decision(input)) break;
	}

	cout << input << endl;
	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#define pi 3.14159
using namespace std;

int main() {
	string str;
	int i;
	while(getline(cin, str)) {
		for(i = 0; i < 26; i++) {
			for(int j = 0; j < str.size(); j++) {
				if(str[j] != ' ' && str[j] != '.') {
					if(str[j] != 'a') {
						str[j] -= 1;
					} else str[j] = 'z';
				}
			}
			for(int j = 0; j < str.size() - 4; j++) {
				if(str[j] == 't' && str[j + 1] == 'h') {
					if(str[j + 2] == 'e' ) {
						cout << str <<endl;
						i = 26;
						break;
					} else if(str[j + 2] == 'i' && str[j + 3] == 's'){
						cout << str <<endl;
						i = 26;
						break;
					} else if(str[j + 2] == 'a' && str[j + 3] == 't') {
						cout << str <<endl;
						i = 26;
						break;
					}
				}
			}
			
		}
	}

	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <cstdio>
#include <cctype>
#define N 100
using namespace std;

void hukugou(char str2[]){
  int i;

  while(1){

    for(i = 0;str2[i] != '\0';i++){
      if(str2[i] != ' ' && str2[i] != '\n' && str2[i] != '.'){
	str2[i] = (str2[i] - 'a' + 1) % 26 + 'a';
      }
    }

    if(strstr(str2, "the") != NULL || strstr(str2, "this") != NULL || strstr(str2, "that") != NULL){
      cout << str2;
      break;
    }
  }

}

int main(){
  char str[N];

  while(fgets(str, sizeof(str), stdin) != NULL){

  hukugou(str);

  }

  return 0;
}