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 <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[] = {"this","the","that"};
    vector<string> in;
    while(true){
	string temp;
	cin >> temp;
	if(cin.eof()) break;
	in.PB(temp);
	if(temp[temp.length()-1] == '.') {
	    in[in.size()-1].erase(in[in.size()-1].begin() + in[in.size()-1].size()-1);
	    break;
	}
    }
    bool f = false;
    int d = 1;
    REP(i,30){

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

    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <math.h>
#include <vector>
#include <set>

using namespace std;
typedef long long LL;
static const double EPS = 1e-9;

#define FOR(i,k,n) for (int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n) 

int main(void){  
  vector<string> words;
  string bf;
  int s = 0;
  while(cin>>bf) words.push_back(bf);
  REP(i,words.size()){
    if(words[i].size()>2){
      REP(j,26){
        REP(k,words[i].size()){
          if(words[i][k] >= 'a' && words[i][k] <= 'z' )
            words[i].replace(k, 1, 1,
                'a' + ( words[i][k] + 1 - 'a')%('z'-'a'+1) );
        
          if(words[i] == "the"||words[i] == "this" || words[i] == "that" ||
             words[i] == "the." || words[i] == "this." || words[i] == "that." )
            s = j;
        }
      }
    }
  }
  REP(i,words.size())
    REP(j,words[i].size())
      if(words[i][j] >= 'a' && words[i][j] <= 'z' )
        words[i].replace(j, 1, 1, 'a' + (words[i][j] + s+1 - 'a')%('z'-'a'+1) );
  cout << words[0];
  FOR(i,1,words.size())
    cout << " " << words[i];
  cout << endl;
}

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

int caesar[26][255], x, enkrip[100];
int thiss[] = {'t', 'h', 'i', 's'}, the[] = {'t', 'h', 'e'}, that[] = {'t', 'h', 'a', 't'};
string s;
int main() {
	for(int i = 0; i <= 25; i++) {
		for(char j = 'a'; j <= 'z'; j++) {
			if(j + i > 'z') x = j + i - 26; else x = j + i;
			caesar[i][x] = j;
		}
	}
	getline(cin, s);
	for(int k = 0; k <= 25; k++) {
		int l = 0, z = 0, zz = 0;
		for(int i = 0, j = s.size(); i != j; i++) {
			if(s[i] <= 'z' && s[i] >= 'a') {
				enkrip[i] = caesar[k][s[i]];
				if(enkrip[i] == thiss[l]) l++;
				if(enkrip[i] == the[z]) z++;
				if(enkrip[i] == that[zz]) zz++;
			} else enkrip[i] = s[i];
		}
		if(l == 4 || z == 3 || zz == 4) {
			for(int i = 0, j = s.size(); i != j; i++) {
				printf("%c", enkrip[i]);
			}
			break;
		}
	}
	printf("\n");
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cctype>
#include <cstdio>
#include <math.h>
#include <map>
#include <queue>
#include <string>
using namespace std;

char ch;
string text;

int main() {
    while(getline(cin,text)){
    	for(int i=0;i<26;i++){
    		for(int j=0;j<text.size();j++){
    			if(text[j]>='a'&&text[j]<='y')text[j]+=1;
    			if(text[j]=='z')text[j]='a';
    		}
    		int p=text.find("the"),q=text.find("this"),r=text.find("that");
    		if(p!=string::npos||q!=string::npos||r!=string::npos){
    			cout<<text<<endl;
    			break;
    		}
    	}
    }
}

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

using namespace std;

bool CheckText(string x)
{
    if(x.find("this") < x.length())
    {
        return false;
    }
    else if(x.find("the") < x.length())
    {
        return false;
    }
    else if(x.find("that") < x.length())
    {
        return false;
    }
    else
    {
        return true;
    }
}

int main()
{
    string Alphabet = "abcdefghijklmnopqrstuvwxyza";
    string Text;

    getline(cin, Text);

    while(CheckText(Text))
    {
        for(unsigned int a = 0; a < Text.length(); a++)
        {
            for(int b = 0; b < 26; b++)
            {
                if(Text[a] == Alphabet[b])
                {
                    Text[a] = Alphabet[b+1];
                    break;
                }
                else if(Text[a] == ' ')
                {
                    break;
                }
            }
        }

    }

    cout << Text << endl;


}

C++: #define _USE_MATH_DEFINES
#include <iostream>
#include <sstream>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>

using namespace std;

int main()
{
	string str;
	while(getline(cin,str)){
		for(int rot = 0;rot< 'z' - 'a' + 1;rot++){
			string tmp = str;
			for(int i=0; i<str.size(); i++){
				if(tmp[i] == ' ') continue;
				if(tmp[i] == '.') continue;
				tmp[i] = (rot + tmp[i]-'a') % ('z' - 'a' + 1) + 'a';
			}
			//cout << tmp << endl;
			if(tmp.find("the") != string::npos
				|| tmp.find("this") != string::npos
				|| tmp.find("that") != string::npos)
			{
				cout << tmp << endl;
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <stdio.h>

#define NUM_OF_ALPHABET ('z' - 'a' + 1)

bool isValidResult(const std::string str);
bool decodeStr(const std::string srcStr, std::string& dstStr, int decodeNum);

int main(void)
{
	std::string inputStr;
	std::string outputStr;

	char line[100];
	fgets(line, sizeof(line), stdin);
	inputStr = line;

	for (int i = 0; i < NUM_OF_ALPHABET; i++) {
		if (decodeStr(inputStr, outputStr, i)) {
			std::cout << outputStr;
			break;
		}
		outputStr.clear();
	}
	return 0;
}

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

bool decodeStr(const std::string srcStr, std::string& dstStr, int decodeNum)
{
	for (int i = 0; i < srcStr.size(); i++) {
		if (srcStr.at(i) >= 'a' && srcStr.at(i) <= 'z') {
			unsigned char tmpChar;
			tmpChar = srcStr.at(i) + decodeNum;
			if (tmpChar > 'z') {
				tmpChar -= NUM_OF_ALPHABET;
			}
			dstStr.push_back(tmpChar);
		}
		else {
			dstStr.push_back(srcStr.at(i));
		}
	}
	if (isValidResult(dstStr)) {
		return true;
	}
	else {
		return false;
	}
}