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 <bits/stdc++.h>
using namespace std;
#define FOR(i, s, n) for(int i = s; i < (int)n; i++)
#define per(i, n) for(int i = n; i >= 0; i--)
#define ROF(i, s, n) for(int i = s; i >= (int)n; i--)
#define FORIT(i, A) for (auto i : A)
#define PRINT(x) cout << (x) << "\n"
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MP make_pair
#define EACH(i, n) for (__typeof((n).begin()) i = (n).begin(); i != (n).end(); ++i)
#define SZ(a) int((a).size())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define CLR(a) memset((a), 0 ,sizeof(a))
#define NCLR(a) memset((a), -1 ,sizeof(a))
#define dump(x) cout << #x << " = " << (x) << "\n";
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << "\n";
#define sq(n) (n) * (n)
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef priority_queue<int> maxpq;
typedef priority_queue< int, vector<int>, greater<int> > minpq;
typedef complex<double> P;
static const double EPS = 1e-10;
static const double PI = acos( -1.0 );
static const int mod = 1000000007;
static const int INF = 1 << 30;
static const LL LL_INF = 1152921504606846976;
static const int dx[] = { -1, 0, 1, 0, 1, -1, 1, -1 };
static const int dy[] = { 0, -1, 0, 1, 1, 1, -1, -1 };

string str;
map<char, char> change;

int main() {
	for ( int i = 0; i < 26; i++ ) {
		change[ i + 'a' ] = ( i + 1 ) % 26 + 'a';
	}
	getline( cin, str );
	for ( ;; ) {
		for ( int j = 0; j < str.size(); j++ ) {
			if ( str[ j ] >= 'a' && str[ j ] <= 'z' ) {
				str[ j ] = change[ str[ j ] ];
			}
		}
		bool is_can = false;
		for ( int j = 2; j < str.size(); j++ ) {
			if ( str.substr( j - 2, 3 ) == "the" ) {
				is_can = true;
				break;
			}
		}
		for ( int j = 3; j < str.size(); j++ ) {
			if ( str.substr( j - 3, 4 ) == "that" || str.substr( j - 3, 4 ) == "this" ) {
				is_can = true;
				break;
			}
		}
		if ( is_can ) {
			break;
		}

	}
	printf( "%s\n", str.c_str() );
	return 0;
}

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

int main() {
	int i, j;
	string news;
	while (getline(cin, news)){
		for (i = 1; i <= 25; i++) {
			for (j = 0; j < news.size(); j++){
				if (news[j]>'a' && news[j] <= 'z')news[j] -= 1;
				else if (news[j] == 'a') news[j] = 'z';
			}
			for (j = 0; j < news.size() - 3; j++) {
				if ((news[j] == 't'&&news[j + 1] == 'h') && (news[j + 2] == 'e' || (news[j + 2] == 'i'&&news[j + 3] == 's') || (news[j + 2] == 'a'&&news[j + 3] == 't'))) {
					goto end;
				}
			}
		}
	end:
		cout << news << endl;
	}
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <string>
#include <algorithm>
#include <string>
#include <climits>
#include <iomanip>
#include <utility>

#define REP(i, n) for (int (i) = 0; (i) < (int)(n); (i)++)
#define REG(i, a, b) for (int (i) = ((int)(a)); (i) < ((int)(b)); i++)
#define ALL(V) (V).begin(), (V).end()
#define PRINT(STR) cout << (STR) << endl
#define DEBUG(X) cerr << X << " (" << __LINE__ << ", " << __func__ << " )" << endl;

typedef long long ll;
using namespace std;

int main() {
	cin.tie(0); //?????±?????????????????????
	ios::sync_with_stdio(false); //printf??¨??±??????????????????
	string str;
	while (getline(cin, str)) {
		string newstr = str;
		for (int i = -26; i <= 26; i++) {
			for (int j = 0; j < str.size(); j++) {
				if (newstr[j] != ' ' && newstr[j] != '.') {
					newstr[j] = str[j] + i;
				}
			}
			if (newstr.find("the", 0) != string::npos ||
					newstr.find("this", 0) != string::npos ||
					newstr.find("that", 0) != string::npos) {
				cout << newstr << endl;
				break;
			}
		}
	}
	return 0;
}

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] >= 'a' && str[j] <= 'z')
	  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);
      if((f_the != string::npos && f_the == 0 && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\0')) || (f_this != string::npos && f_this == 0 && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\0')) || (f_that != string::npos && f_that == 0 && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\0')))
	cout << str << endl;
      else if((f_the != string::npos && (str[(f_the - 1 < 0) ? 0 : f_the - 1] == ' ' || str[(f_the - 1 < 0) ? 0 : f_the - 1] == '.' || str[(f_the - 1 < 0) ? 0 : f_the - 1] == '\n') && (str[f_the + 3] == ' ' || str[f_the + 3] == '.' || str[f_the + 3] == '\0')) || (f_this != string::npos && (str[(f_this - 1 < 0) ? 0 : f_this - 1] == ' ' || str[(f_this - 1 < 0) ? 0 : f_this - 1] == '.' || str[(f_this - 1 < 0) ? 0 : f_this - 1] == '\n') && (str[f_this + 4] == ' ' || str[f_this + 4] == '.' || str[f_this + 4] == '\0')) || (f_that != string::npos && (str[(f_that - 1 < 0) ? 0 : f_that - 1] == ' ' || str[(f_that - 1 < 0) ? 0 : f_that - 1] == '.' || str[(f_that - 1 < 0) ? 0 : f_that - 1] == '\n') && (str[f_that + 4] == ' ' || str[f_that + 4] == '.' || str[f_that + 4] == '\0')))
	cout << str << endl;	 
    }
  }
}

C++: #include<iostream>
#include<cstring>
#include<stdio.h>
using namespace std;

int main(){
  char a[100],b[100];
  for(int i;i<100;i++){
    a[i]='\0';
    b[i]='\0';
  }
  gets(a);
  int i=0;
  while(i<26){
    for(int j=0;!(a[j]=='\0');j++){
      if(0x61<=a[j]+i&&a[j]+i<=0x7A)
	b[j]+=i;
      else if(0x61<=a[j]&&a[j]<=0x7A){
	b[j]=a[j]-26+i;
      }
      else if(a[j]==' ')
	b[j]=' ';
      else if(a[j]=='.')
	b[j]='.';
    }
    if(strstr(b,"the")||strstr(b,"this")||strstr(b,"that"))
      break;
    i++;
  }
  for(int k=0;a[k]!='\0';k++)
    cout<<b[k];
  cout<<'\n';
  return 0;
}

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

using namespace std;

string decode(string s, int v) {
    string ans = s;
    for(int i = 0; i < (int) s.size(); i++) {
        if(s[i] >= 'a' && s[i] <= 'z') {
            ans[i] = (s[i] + v) % 26 + 'a';
        }
    }
    return ans;
}

int main() {
    string s;
    while(getline(cin, s)) {
        for(int i = 0; 26; i++) {
            string tmp = decode(s, i);
            if(tmp.find("this") != string::npos || tmp.find("the") != string::npos || tmp.find("that") != string::npos) {
                cout << tmp << endl;
                break;
            }
         }
    }
    return 0;
}