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
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <queue>
#include <iterator>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int gcd(int a, int b){
   int tmp;
   while(a%b==0){
      tmp=a%b;
      a=b;
      b=tmp;
   }
}

int lcm(int a,int b){
   return a*b/gcd(a,b);
}

bool prime_number(int n){
   if(n < 2){
      return false;
   }
   else if(n == 2){
      return true;
   }
   if(n % 2 == 0){
      return false;
   }
   for(int i=3;i<=n/i;i+=2){
      if(n % i == 0) return false;
      return true;
   }
}

int main(){
   vector<string> a;
   string b;
   int x=0;

   while(cin>>b){
      if(!x){
         if(b.size()==3&&b[0]-'t'==b[1]-'h'&&b[1]-'h'==b[2]-'e')
            x=b[0]-'t';
         else if(b.size()==4&&b[0]-'t'==b[1]-'h'&&b[1]-'h'==b[2]-'i'
            &&b[2]-'i'==b[3]-'s') x=b[0]-'t';
         else if(b.size()==4&&b[0]-'t'==b[1]-'h'&&b[1]-'h'==b[2]-'a'
            &&b[2]-'a'==b[3]-'t') x=b[0]-'t';     
      }
      a.PB(b);
   }
   REP(i,a.size()){
      REP(j,a[i].size()) if(a[i][j]>='a'&&a[i][j]<='z') a[i][j]-=x;
   }
   REP(i,a.size()){
      cout << a[i];
      if(i!=a.size()-1) cout << " ";
   }
   cout << endl;
   return 0;
}

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

bool IncludeKeyWords(const string& Sentence)
{
	if(Sentence.find("the")  <= 80) return true;
	if(Sentence.find("this") <= 80) return true;
	if(Sentence.find("that") <= 80) return true;
	return false;
}

string OneShift(string Sentence)
{
	for(int i = 0; i < Sentence.size(); i++){
		if(97 < Sentence[i] && Sentence[i] < 123){
			Sentence[i] --;
		}else if(Sentence[i] == 97){
			Sentence[i] = 122;
		}
	}
	return Sentence;
}

string Decrypt(string Sentence)
{
	int RoopCount = 0;
	while(IncludeKeyWords(Sentence) == false){
		assert(RoopCount < 26);
		Sentence = OneShift(Sentence);
		RoopCount++;
	}
	return Sentence;
}

int main()
{
	while(true){
		string Sentence;
		getline(cin, Sentence);
		if(cin.eof() == true) break;
		string DecryptedSentence = Decrypt(Sentence);
		cout << DecryptedSentence << 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<26;k++){
        
        bool f = false;
        
        for(int i=0;S[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]=='s') || (S[i-1]=='h' && S[i]=='t'))
                    f=true;
            }
        }
        
        if(f) break;
    }
    
    for(int i=0;S[i]!='\0';i++)
        printf("%c",S[i]);
    
    return 0;
}