Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

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 scanner.Scan() {
		infos := strings.Split(scanner.Text(), " ")
		plain := make([]string, len(infos))
		// 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<algorithm>
#include<cstdio>
#include<cmath>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define MOD 1000000007
#define rep(i,n) for(i=0;i<n;i++)
#define loop(i,a,n) for(i=a;i<n;i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

typedef vector<int> vi;
typedef pair<int,int> pii;

int main(void) {
  int i,j,k;
  string s;
  while(getline(cin,s)){
    int n=0;
    rep(i,s.size())if(s[i]==' ')n++;
    n++;
    vector<string> word(n);
    i=0;
    rep(j,n){
      while(s[i]>='a' && s[i]<='z')
	word[j].push_back(s[i]),i++;
      i++;
    }
    rep(k,26){
      bool c=false;
      rep(i,n)rep(j,word[i].size())
	if(word[i][j]=='z')word[i][j]='a';
	else word[i][j]=word[i][j]+1;
      rep(i,n)
	if(word[i]=="the" || word[i]=="this" || word[i]=="that"){
	  c=true;break;
	}
      if(c){
	rep(i,n){
	  if(i)cout<<" ";
	  cout<<word[i];
	}
	cout<<"."<<endl;
	break;
      }
    }
  }
}

C++:  
 #include<iostream>
 #include<stdio.h>
 #include<string>
 #include<math.h>
 #include<iomanip>
 #include<algorithm>
 #include<string.h>
 #include<cctype>
 #include<map>
 #include<set>
 #include<vector>
 #include<sstream>
 #include<stack>
 
 using namespace std;
  
 int main()
 {
   string a,b;
   while(getline(cin,a))
   {
     for(int shift=0;shift<26;shift++)
     {
       b="";
       for(int i=0;i<a.length();i++)
       {
         if(a[i]>='a'&&a[i]<='z')
         { 
           if(a[i]+shift>'z') b+=(a[i]+(shift-26));
           else b+=(a[i]+shift);
         }         
         else b+=a[i]; 
       }
       if(b.find("the")!=string::npos||b.find("this")!=string::npos||b.find("that")!=string::npos) break;
       else continue;
     }             
     cout<<b<<endl;
   }
   //while(1);      
   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];
    
    gets(S);
    
    while(1){
        
        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]=='a' && S[i]=='t'))
                        f=true;
            }
        }
        
        if(f) break;
    }
    
    printf("%s\n",S);
    
    return 0;
}

C++: #include<iostream>
#include<cstring>
#define MAX 90
using namespace std;
char str[MAX];
bool contain(){
	for(int i=0;str[i]!='\0';i++){
		if(str[i]=='t'){
			if(strncmp(&str[i],"the",3)==0)
			return 1;
			else if(strncmp(&str[i],"this",4)==0)
			return 1;
			else if(strncmp(&str[i],"that",4)==0)
			return 1;
		}
	}
	return 0;
}
void rotate(){
	for(int i=0;str[i]!='\0';i++)
	if(str[i]=='z')
	str[i]='a';
	else if(isalpha(str[i]))
	str[i]=(char)(str[i]+1);
}
int main(){
	while(cin.getline(str,MAX)){
		for(int i=0;i<26;i++){
			rotate();
			if(contain())
				break;
		}
		cout<<str<<endl;
	}
	return 0;
}

C++: 
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
int main(){
  string s;
  int pl=0;
  while(getline(cin,s)){
    if(s=="\n"&&s=="EOF")  break;
  for(int i =-30;i<30;i++){
    for(int j = 0; j < s.size(); j++){
      if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'e'){
	pl = i;
	break;
      }
      if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'a' && s[j+3]+i=='t'){
	pl = i;
	break;
      }
      if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'i' && s[j+3]+i=='s'){
	pl = i;
	break;
      }
    }
    if(pl!=0) break;
  }
  for(int i=0;i <s.size();i++){
    if(s[i]<='z' && s[i]>='a') s[i] += pl;
    if(s[i]!=' ' && s[i]!=',' && s[i]!='.'){
    	if(s[i]>'z') s[i]-=26;
    	else if(s[i]<'a') s[i]+=26;
    }
  } 
  cout<<s<<endl;
  pl=0;
  }
}

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

using namespace std;

void Shift(string *str, int shift, int vec) {
  for (int str_i = 0; str_i < str->size(); str_i++)
    if (!isspace((*str)[str_i]) && (*str)[str_i] != '.')
      (*str)[str_i] += vec * shift;
}

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

int main() { 
  string input_str;

  int shift = 1;
  while (getline(cin, input_str)) {
    while (1) {
      Shift(&input_str, shift, -1);
      if (FindTarget(input_str))
        break;
      Shift(&input_str, shift, 1);
      shift++;
    }
    cout << input_str << endl;
  }

  return 0;
}

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

using namespace std;

void solve()
{
	string str;
	while(getline(cin, str))
	{
		string word;
		int n = str.size();
		for(int j = 0; j < 26; ++j)
		{
			word.clear();
			for(int i = 0; i < n; ++i)
			{
				if('a' <= str[i] && str[i] <= 'z')
				{
					word += (str[i] + j -'a') % 26 + 'a';
				}
				else
				{
					word += str[i];
				}
			}
			if(word.find("this") != -1 || word.find("the") != -1 || word.find("that") != -1)
			{
				cout << word << endl;
			}
		}
	}
}

int main()
{
	solve();
	return(0);
}