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
//------------------------------------------
#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(){
   string a;

   while(getline(cin,a)){
      while(a.find("the")==string::npos&&a.find("this")==string::npos&&a.find("that")==string::npos)
         REP(i,a.size()){
            if(a[i]=='z') a[i]='a';
            else if(a[i]>='a'&&a[i]<='z') a[i]++;
         }
      cout << a << endl;
   }
   return 0;
}

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

using namespace std;

int main(){
  string text;
  while(getline(cin,text,'\n')){
    for(int i=0;i<25;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<string>
using namespace std;
main(){
	string str;
	int tmp,b;
	while(getline(cin,str)){
		tmp='t'-str[0];
		for(int i=0;i<str.size();++i){
			if(str[i]>='a' && str[i]<='z'){
				if(str[i]>='r')str[i]-=26;
				str[i]+=tmp;
				if(str[i]<'a')str[i]+=26;
				else if(str[i]>'z')str[i]-=26;
			}
		}
		string str2="    ";
		for(int i=0;i<=3,i<=3;++i)str2[i]=str[i];
		if(str2=="this" || str2=="the " || str2=="that")cout<<str<<endl;
	}
}

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

int attack(string line)
{
    static const string cmp[3] = {"the", "this", "that"};
    istringstream iss(line);

    for (string word; iss >> word;) {
        char first = word[0];
        for (string c: cmp)
            if (c.size() == word.size()) {
                int i = 1;
                for (; i < c.size(); i++)
                    if ((c[i] - 't') % 26 != (word[i] - first) % 26)
                        break;
                if (i == c.size()) {
                    int div = ('t' - first) % 26;
                    return (div >= 0) ? div : 26 + div;
                }
            }
    }

    return -1;
}

inline int rotN(int x, int n)
{
    if (isalpha(x))
        return (x - 'a' + n) % 26 + 'a';
    else
        return x;
}

int main()
{
    int rot;
    string line;

    while (getline(cin, line)) {

        rot = attack(line);

        for (auto x : line)
            cout << (char) rotN(x, rot);

        cout << endl;
    }

    return 0;
}

C++: #define scanf_s scanf
#define gets_s gets
#include <stdio.h>
#include <string>
#include <iostream>
#include <math.h>
using namespace std;
#define MAX 81
#define _MAX 100
#define ABC 26
int main(void)
{
	int n, s = 0, x, y, r = 0, a, b;
	int sum_n[50][3] = { 0 };
	char sum[50][_MAX], str[_MAX], bstr[_MAX], num[11] = { "0123456789" };
	//
	while(gets_s(str) != EOF){
		for (int i = 0; str[i] != '\0'; ++i) {
			if (str[i] - 't' == str[i + 1] - 'h') {
				a = str[i] - 't';
				if ((str[i + 2] - a + 'z') % 'z' == 'e') { b = a; break; }
				else if ((str[i + 2] - a + 'z') % 'z' == 'i' + ABC && (str[i + 3] - a + 'z') % 'z' == 's') { b = a; break; }
				else if ((str[i + 2] - a + 'z') % 'z' == 'a' + ABC && (str[i + 3] - a + 'z') % 'z' == 't') { b = a; break; }
			}
		}
		for (int i = 0; str[i] != '\0'; ++i) {
			if ('a' <= str[i] && str[i] <= 'z') {
				printf("%c", (str[i] - a + 'z') % 'z');
			}
			else { printf("%c", str[i]); }
		}
		printf("\n");
	}
}