Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func incrementByte(b byte) byte {
	if b >= 97 && b < 122 {
		return b + 1
	} else if b == 122 {
		return 97
	}
	return b
}

func main() {
	scanner.Split(bufio.ScanLines)

	for {
		line := nextString()
		if len(line) == 0 {
			break
		}
		for i := 0; i <= 26; i++ {
			decoded := []byte{}
			for j := 0; j < len(line); j++ {
				decoded = append(decoded, incrementByte(line[j]))
			}
			line = string(decoded)
			if strings.Contains(line, "the") || strings.Contains(line, "this") || strings.Contains(line, "that") {
				fmt.Println(line)
				break
			}
		}
	}
}

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

using namespace std;

string answer;

bool saiki( int advance, string target )
{
	for( int i = 0;i < target.size();i++ ){
		if( target[i] >= 'a' && target[i] <= 'z' ){target[i]+=advance; if( target[i] < 'a' || target[i] > 'z' ) return false;}
	}
	if( target.find( "the" ) != string::npos || target.find( "that" ) != string::npos || target.find( "this" ) != string::npos ){ answer = target;return true;  }
	else return saiki( advance, target );
}

int main(int argc, char const* argv[])
{
	string str;

	while( getline( cin, str ) ){
		if(saiki( 1 ,str )){
			cout << answer << endl;
			continue;
		}
		if( saiki( -1 , str ) ){
			cout << answer << endl;
			continue;
		}
	}
	return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
int main(){
	string s;
	while(getline(cin, s)){
		for(int i = 0; i < 26; i++){
			for(int i = 0; s[i] != '\0'; i++){
				if(s[i] >= 97 && s[i] <= 122) s[i] = (s[i] - 97 + 1) % 26 + 97;
			}
			if(s.find("the", 0) != string::npos || s.find("this", 0) != string::npos || s.find("that", 0) != string::npos){
				cout << s << endl;
				break;
			}
		}
	}
	return 0;
}

C++: //0017 Caesar Chipher

//es²ÆÉAAt@xbgAXy[XAsIhAüsªÜÜêéÅå80¶Ì¶ñª^¦çêé
//µ½ÃÉÍAthe,this,thatÌ¢¸ê©ªK¸ÜÜêé
//EOFªüÍ³êéÜÅAµ½¶ñðoÍ¹æ

#include<iostream>
#include<string>
#include<cctype>
using namespace std;

int main(void)
{
	string str;
	//óàÜÞêsð¾é½ßÉgetline()AÈºcin.getline(str)ªÅ«È¢ñ¾
	while( getline(cin, str) )
	{
		int i;
		int s = str.size();
		const string::size_type N = string::npos;
		while( str.find("the")==N && str.find("this")==N && str.find("that")==N )
		{
			for(i = 0; i < s; i++)
			{
				if(isalpha(str[i]))
				{
					str[i] = (str[i]-'a'+1)%26+'a';
				}
			}
		}
		cout << str << endl;
	}
	return 0;
}

C++: #include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
const ld eps = 1e-9;

//// < "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\a.txt" > "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\b.txt"


int main() {
	string st;
	vector<string>ths{ "the","this","that" };
	int a; cin >> a;
	while (getline(cin, st)) {
		for (int i = 1; i < 26; ++i) {
			string nextst(st);
			for (auto&c : nextst) {
				int n = c - 'a';
				if (n < 0 || n >= 26)continue;
				n += i;
				n %= 26;
				c = 'a' + n;
			}
			bool ok = false;
			for (auto th : ths) {
				if (nextst.find(th) != -1)ok = true;
			}
			if (ok) {
				cout << nextst << endl;
				break;
			}
		}
	}
	return 0;
}

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

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    string str;
    while(getline(cin, str)) {
        for(int i=0; i<25; i++) {
            if(str.find("the")!=string::npos) break;
            if(str.find("this")!=string::npos) break;
            if(str.find("that")!=string::npos) break;
            for(int i=0, l=str.length(); i<l; i++) {
                if(str[i]=='z') str[i]='a';
                else if(islower(str[i])) ++str[i];
            }
        }
        cout<<str<<'\n';
    }
    return 0;
}

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

using namespace std;


int main(){

	string line;

	while(getline(cin, line)){

		string str[80], ans[80];
		int count = 0;
		int flag = 0;
		int slide;

		//???????????????
		/*
		string temp;
		for(int i=0 ; i<line.size()-1 ; i++){
			temp += line[i];
		}
		line = temp;
		*/
		

		//???????????????????????¨???????´?
		for(int i=0 ; i<line.size() ; i++){
			if(line[i] == ' '){
				count++;
			}else{
				str[count] += line[i];
				ans[count] = str[count];
			}
		}
		count++;


		for(int i=1 ; i<=26 ; i++){
			for(int j=0 ; j<count ; j++){
				for(int k=0 ; k<str[j].size() ; k++){
					if(str[j][k] >= 'a' && str[j][k] <= 'z'){
						str[j][k]++;
						if(str[j][k] > 'z'){
							str[j][k] = str[j][k] - 'z' + 'a' -1;
						}
					}
					if(str[j][k] == 'h' && str[j][k-1] == 't'){
						flag = 1;
						slide = i;
						break;
					}
				}

				/*
				if(str[j] == "this" || str[j] == "the" || str[j] == "that"
						|| str[j] == "this." || str[j] == "the." ||str[j] == "that."){
					flag = 1;
					slide = i;
					break;
				}
				*/
				if(flag == 1)break;
			}
			if(flag == 1)break;
		}

		for(int i=0 ; i<count ; i++){
			for(int j=0 ; j<ans[i].size() ; j++){
				if(ans[i][j] >= 'a' && ans[i][j] <= 'z'){
					if((ans[i][j] + slide) > 'z' ){
						ans[i][j] = ans[i][j] - 'z' + 'a' + slide -1;
					}else{
						ans[i][j] = ans[i][j] + slide ;
					}
				}
			}
		}

		//cout << ans[0] << endl;

		for(int i=0 ; i<=count ; i++){
			cout << ans[i];
			if(i < count) cout << ' ';
		}
		cout << endl;

	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main() {
	string str, the = " the", dis = " this", that = " that";
	int zure, count = 0, i = 0;
	string judge = " ";
	bool bo = false;
	getline(cin, str);
		for (int j = 0; j < str.size(); j++) {
			zure = str[i] - 't';
			if (str[j] != ' ' && str[j]!='.') {
				if (str[j] - zure>='a'&&str[j]-zure<='z') {
					judge += str[j] - zure;
				}
				else if(str[j]-zure>'z'){
					judge += str[j] - 26 - zure;
				}
				else {
					judge += str[j] + 26 + zure;
				}
			}
			if (str[j] == ' ' || j == str.size() - 1) {
				if (judge == " the" || judge == " this" || judge == " that") {
					bo = true;
					break;
				}
				else {
					i = j+1 ;
					judge = " ";
				}
			}
		}
	for (int i = 0; i < str.size(); i++) {
		if (str[i] >= 'a'+abs(zure) && str[i] <= 'z' - abs(zure)) {
			str[i] -= zure;
		}
		else if ((str[i]-abs(zure) < 'a' || str[i]+abs(zure) > 'z') && str[i]!=' ' && str[i]!='.') {
			if (str[i] + zure > 'z') {
				str[i] -= zure; 
			}
			else if (str[i] - zure > 'z') {
				str[i] -= 26 + zure;
			}
			else if (zure < 0) {
				str[i] -= zure;
			}
			else {
				str[i] += 26 - zure;
			}
		}
		cout << str[i];
	}
	cout << endl;
	return 0;
}

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

bool decision(string input){
	for(int i = 0; i < input.size()-3; i++){
		if((input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'e') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'i' && input[i+3] == 's') ||
			(input[i] == 't' && input[i+1] == 'h' && input[i+2] == 'a' && input[i+3] == 't')){
			return true;
		}
	}
	return false;

}

int main(){
	string input;
	getline(cin, input);

	while(getline(cin, input);){
		for(int i = 0; i < input.size(); i++){
			if('a' <= input[i] && input[i] <= 'z'){
				if(input[i] != 'z'){
					input[i] += 1;
				}else{
					input[i] = 'a';
				}
			}
		}
		if(decision(input)) cout << input << endl;;
	}

	return 0;
}