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 <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)) {
    Shift(&input_str, shift, 1);
    if (FindTarget(input_str))
      break;
    Shift(&input_str, shift, -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>
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;
}

void 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] = 123;
		}
	}
}

int main()
{
	while(true){
		string Sentence;
		getline(cin, Sentence);
		if(cin.eof() == true) break;
		while(IncludeKeyWords(Sentence) == false){
			OneShift(Sentence);
		}
		cout << Sentence << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

bool is_finish(string s)
{
    string str;
    stringstream ss(s);
    while (ss >> str) {
        if (str == "the" ||
            str == "this" ||
            str == "that") return 1;
    }
    return 0;
}

int main()
{
    string s;
    getline(cin, s);
    for (int i = 0; i < 26; i++) {
        for (char &c: s) {
            if (islower(c)) {
                c = c + 1;
                if (c > 'z') c = 'a';
            }
        }
        if (is_finish(s)) {
            break;
        }
    }
    cout << s << endl;
    return 0;
}

C++: #include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <cstdlib>
#include <algorithm>
#include <iterator>
#include <stack>
typedef long long int lli;
using namespace std;

int main(){
	string str;
	while(getline(cin,str)){
		for(int i=0; i<=25; ++i){
			string tmp=str;
			for(int j=0; j<str.size(); ++j){
				if('A'<=str[j]&&str[j]<='Z'){
					if('A'<=tmp[j]+i&&tmp[j]+i<='Z'){
						tmp[j]=tmp[j]+i;
					} else {
						tmp[j]=tmp[j]+i+'A'-'Z'-1;
					}
				} else if('a'<=str[j]&&str[j]<='z'){
					if('a'<=tmp[j]+i&&tmp[j]+i<='z'){
						tmp[j]=tmp[j]+i;
					} else {
						tmp[j]=tmp[j]+i+'a'-'z'-1;
					}
				}
			}
			if(tmp.find("the")!=-1||tmp.find("this")!=-1||tmp.find("that")!=-1){
				cout << tmp << endl;
				break;
			}
		}
	}
	return 0;
}

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

bool find(string str, string can) {
  string tmp_can = ' ' + can + ' ';
  string tmp_str = ' ' + str + ' ';
  for (int i = 0; i < tmp_str.length(); ++i) {
    if (string::npos != tmp_str.find(tmp_can, i)) {
      return true;
    }
  }
  return false;
}

int main() {
  string str;
  string candies[] = {"this", "the", "that"};
  while(getline(cin, str)) {
  for (int m = 0; m < 25; ++m) {
    for (int i = 0; i < str.length(); ++i) {
      if (str[i] == ' ') {
        continue;
      }
      if (str[i] == ',' || str[i] == '.') {
        str[i] = ' ';
        continue;
      }
      int char_id = static_cast<int>(str[i]) - 97;
      int shifted = static_cast<int>(char_id + 1);
      str[i] = static_cast<char>(shifted % 26 + 97);
    }
    for (int i = 0; i < sizeof(candies) / sizeof(candies[0]); ++i) {
      if (find(str, candies[i])) {
        cout << str << endl;
        break;
      }
    }
  }
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
	string s,t;
	while(getline(cin,s)){t=s;
	for(int i=0;i<26;i++){
		s=t;
		for(int j=0;j<s.size();j++){
			if(s[j]>='a'&&s[j]<='z')for(int k=0;k<i;k++){
				s[j]++;
				if(s[j]>'z')s[j]-=26;
			}
		}
		if((s.find("the")!=s.npos||s.find("this")!=s.npos||s.find("that")!=s.npos))break;
	}
	cout<<s<<endl;}
}

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b) - 1;i>=(a);i--)
#define REP(i,n) for(int i=0;i<(n);i++)
#define RREP(i,n) for(int i=n-1;i>=0;i--)

#define PB push_back
#define INF INT_MAX/3
#define ALL(a) (a).begin(),(a).end()
#define CLR(a) memset(a,0,sizeof(a))

typedef long long int ll;

using namespace std;

int main(){

    string s[] = {"the","this","that"};
    string in;
    while(true){
	getline(cin,in);
	if(cin.eof()) break;
	bool f = false;
	int d = 1;
	REP(i,30){

	    f = true;
	    REP(i,in.size()){
		if(in[i] == '.' || in[i] == ' ' || in[i] == '\n') continue;
		in[i]= (char)( 'a' + ( (int)(in[i] - 'a') + d) % 28);
	    }
	    vector<bool> flgs(3,false);
	    for(int i=0;i<in.size();i++){
		if(in[i] == ' '){
		    REP(j,3){
			if(in.substr(i+1,s[j].size()) == s[j]) flgs[j] = true;
		    }
		}
	    }
	    if(flgs[0] || flgs[1] || flgs[2]) break;
	}
	cout << in << endl;
    }

    return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
int main()
{
    string s;
	while(getline(cin,s)){
		int n=s.size();
		for(int k=0;k<26;k++){
			for(int i=0;i<n;i++)if('a'<=s[i]&&s[i]<='z')s[i]='z'<(s[i]+1)?'a':(s[i]+1);
			if(s.find("the")!=string::npos||s.find("this")!=string::npos||s.find("that")!=string::npos)break;
		}
		cout<<s<<endl;
	}
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include<string>
#include<vector>
int main() {
	std::string s,a;

	while (std::getline(std::cin, s)) {
		int p = s[0] - 't';
		for (int i = 0; i < s.size(); ++i) {
			if (s[i] != ' ' &&s[i] != '.') {
				if (s[i] - p < 'a') {
					a += 'z' - ('a' - (s[i] - p) - 1);
				}
				else a += s[i] - p;
			}
			else a += s[i];
		}
		std::cout << a << std::endl;
	}	
	return 0;
}