Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	for scanner.Scan() {
		var result string
		line := scanner.Text()
		key := make(map[string]string)

		var i int32
		for ; i < 52; i++ {
			makeKey(key, i)
			result = decode(key, line)

			if strings.Contains(result, "the") {
				break
			} else if strings.Contains(result, "this") {
				break
			} else if strings.Contains(result, "that") {
				break
			}
		}

		fmt.Println(result)
	}
}

func makeKey(key map[string]string, shift int32) {
	for i := 'a'; i <= 'z'; i++ {
		cipher := (i + shift)
		if cipher > 'z' {
			cipher = cipher%'z' + 'a' - 1
		} else if cipher < 'a' {
			cipher = cipher + ('z' - 'a') + 1
		}
		key[string(i)] = string(cipher)
	}
}

func decode(key map[string]string, cipher string) string {
	var result string
	for _, v := range cipher {
		if key[string(v)] != "" {
			result += key[string(v)]
		} else {
			result += string(v)
		}
	}
	return result
}

C++: 
#include <stdio.h>
#include <math.h>
#include <string.h>

#define JUDGE(x) (strstr(change,x))

int main(){
    
    int i,j;
    char str[100],change[100];
    while (gets(str) != NULL) {
        for (i=0; i<26; i++) {
            for (j=0; j<strlen(str); j++) {
                if(str[j]>='a' && str[j]<='z')
                    change[j] = str[j]+i >'z'? str[j]+i-26: str[j]+i;
                else
                    change[j] = str[j];
            }
            if (JUDGE("this") || JUDGE("that") || JUDGE("the")) {
                puts(change);
                break;
            }
        }
        memset(str, '\0', sizeof(str));
        memset(change,'\0', sizeof(change));
    }
    
    
    return 0;
    
}

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 <cstdio>
#include <cstring>
#include <string>
using namespace std;

#define rep2(x,from,to) for(int x=(from);(x)<(to);(x)++)
#define rep(x,to) rep2(x,0,to)

int main() {
	while(1) {
		char str[10000] = {0};
		if(gets(str) == NULL) break;
		rep(i,26) {
			if(strstr(str, "the") || strstr(str, "this") || strstr(str, "that")) break;
			for(int j = 0; j < strlen(str); j++) {	
				if(isalpha(str[j])) {
					str[j] != 'z' ? str[j]++ : str[j] = 'a';
				}
			}
		}
		printf("%s\n", str);
	}
	return 0;
}

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

using namespace std;

int main(){
  string text;
  while(getline(cin,text,'\n')){
    for(int i=0;i<26;i++){
      for(int w=0;w<text.size();w++){
	if ('a'<=text[w]&&text[w]<'z')
	  text[w]++;
	else if(text[w]=='z')
	  text[w] = 'a';
      }
      if (text.find("this") != string::npos||text.find("that") != string::npos||text.find("the") != string::npos){
	cout << text << endl;
	break;
      }
    }
  }
}

C++: #include <iostream>
#include <sstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
using namespace std;
 
string solve(string s)
{
    int n = s.size();
    for(;;){
        for(int i=0; i<n; ++i){
            if('a' <= s[i] && s[i] <= 'z'){
                if(s[i] == 'z')
                    s[i] = 'a';
                else
                    ++ s[i];
            }
        }
        istringstream iss(s);
        string s1;
        while(iss >> s1){
            if(s1 == "the" || s1 == "this" || s1 == "that")
                return s;
        }
    }
}
 
int main()
{
    for(;;){
        string s;
        getline(cin, s);
        if(s == "")
            return 0;
 
        cout << solve(s) << endl;
    }
}

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

using namespace std;


int main(){

	string line;

	while(getline(cin, line)){

		string str[80], ans[80];
		int count = 0;
		int flag = 0;
		int slide;

		//???????????????
		/*
		string temp;
		for(int i=0 ; i<line.size()-1 ; i++){
			temp += line[i];
		}
		line = temp;
		*/
		

		//???????????????????????¨???????´?
		for(int i=0 ; i<line.size() ; i++){
			if(line[i] == ' '){
				count++;
			}else{
				str[count] += line[i];
				ans[count] = str[count];
			}
		}
		count++;


		for(int i=1 ; i<=26 ; i++){
			for(int j=0 ; j<count ; j++){
				for(int k=0 ; k<str[j].size() ; k++){
					if(str[j][k] != '.'){
						str[j][k]++;
						if(str[j][k] > 'z'){
							str[j][k] = str[j][k] - 'z' + 'a' -1;
						}
					}
					if(str[j][k] == 'h' && str[j][k-1] == 't'){
						flag = 1;
						slide = i;
						break;
					}
				}

				/*
				if(str[j] == "this" || str[j] == "the" || str[j] == "that"
						|| str[j] == "this." || str[j] == "the." ||str[j] == "that."){
					flag = 1;
					slide = i;
					break;
				}
				*/
			}
			if(flag == 1)break;
		}

		for(int i=0 ; i<count ; i++){
			for(int j=0 ; j<ans[i].size() ; j++){
				if(ans[i][j] != '.'){
					if((ans[i][j] + slide) > 'z' ){
						ans[i][j] = ans[i][j] - 'z' + 'a' + slide -1;
					}else{
						ans[i][j] = ans[i][j] + slide ;
					}
				}
			}
		}

		for(int i=0 ; i<=count ; i++){
			cout << ans[i];
			if(i < count) cout << ' ';
		}
		cout << endl;

	}
	return 0;
}

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

using namespace std;

int main() {
	string str, str2, ans;
	int i, j, l, n = 0;
	while (getline(cin, str)) {
		ans += str;
		ans += '\n';
		if (n != 0) {
			continue;
		}
		l = str.length();
		str2.resize(l);
		for (i = 1; i < 26; i++) {
			for (j = 0; j < l; j++) {
				if (str[j] == '.'||str[j]==' '||str[j]=='\n') {
					continue;
				}
				if (str[j] + i > 'z') {
					str2[j] = str[j] - 26 + i;
				}
				else {
					str2[j] = str[j] + i;
				}
			}
			if (str2.find("the") != string::npos || str2.find("this") != string::npos || str2.find("that") != string::npos) {
				n = i;
				break;
			}
		}
	}
	l = ans.length();
	for (i = 0; i < l; i++) {
		if (ans[i] == '.' || ans[i] == ' ' || ans[i] == '\n') {
			continue;
		}
		if (ans[i] + n > 'z') {
			ans[i] = ans[i] - 26 + n;
		}
		else {
			ans[i] = ans[i] + n;
		}
	}
	cout << ans;
	return 0;
}