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 <bits/stdc++.h>
using namespace std;

//#define int long long
#define reps(i,s,n) for(int (i)=(s);(i)<(n);++(i))
#define rep(i,n) reps(i,0,n)
#define rept(i,n) rep(i,(n)+1)
#define repst(i,s,n) reps(i,s,(n)+1)
#define reprt(i,n,t) for(int (i)=(n);(i)>=(t);--(i))
#define repr(i,n) reprt(i,n,0)
#define each(itr,v) for(auto &(itr):(v))
#define all(c) (c).begin(),(c).end()
#define rall(c) (c).rbegin(),(c).rend()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define tmax(x,y,z) max(x,max(y,z))
#define tmin(x,y,z) min(x,min(y,z))
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define ln '\n'
#define bln(i,n) (((i)==(n)-1)?'\n':' ')
#define dbg(x) cout<<#x" = "<<(x)<<ln<<flush
#define dbga(x,n) {cout<<#x" : ";for(int (i)=0;i<(n);++i){cout<<((x)[i])<<(i==((n)-1)?'\n':' ')<<flush;}}
#define zero(a) memset(a,0,sizeof(a))
#define unq(a) sort(all(a)),a.erase(unique(all(a)),a.end())

typedef complex<double> P;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<string> vst;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<vector<int> > mat;

const ll inf = (ll)1e9+10;
const ll linf = (ll)1e18+10;
const ll mod = (ll)(1e9+7);
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const int ddx[] = {0, 1, 1, 1, 0, -1, -1, -1};
const int ddy[] = {1, 1, 0, -1, -1, -1, 0, 1};
const double eps = 1e-10;

ll mop(ll a,ll b,ll m=mod) {ll r=1;a%=m;for(;b;b>>=1){if(b&1)r=r*a%m;a=a*a%m;}return r;}
ll gcd(ll a,ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b) {return a*b/gcd(a,b);}
bool ool(int x,int y,int h,int w) {return((x<0)||(h<=x)||(y<0)||(w<=y));}
bool deq(double a,double b) {return abs(a-b)<eps;}

struct oreno_initializer {
	oreno_initializer() {
		cin.tie(0);
		ios::sync_with_stdio(0);
	}
} oreno_initializer;

// ━━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…
// .｡.:( ^ω^)・ﾟ＋.｡.:( ^ω^)・ﾟ＋.｡.:( ^ω^)・ﾟ＋.｡.:( ^ω^)・ﾟ＋.｡.:( ^ω^)・ﾟ＋
// ・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・

string s;

signed main() {
	getline(cin,s);
	rep(i,26) {
		if (s.find( "the" ) != string::npos || s.find( "this" ) != string::npos || s.find( "that" ) != string::npos)
			return cout << s << ln, 0;
		rep(j,s.size()) if ('a'<=s[j] && s[j]<='z') {
			s[j]++;
			if (s[j]>'z') s[j] = 'a';
		}
	}
}

C++: #include<iostream>
#include<cstring>
using namespace std;
int main(){
int i,j,k,n;
char s[81];
while(cin.getline(s,81)){
n=strlen(s);
for(j=1;j<27;j++){
for(i=0;i<n;i++){
if(96<s[i]&&s[i]<122)s[i]++;
else if(s[i]==122)s[i]=97;
}
for(i=0;i<n;i++){
if(!strncmp(s+i,"the",3))goto L1;
if(!strncmp(s+i,"this",4))goto L1;
if(!strncmp(s+i,"that",4))goto L1;
}
}
L1:cout<<s<<endl;
}
return 0;
}

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

using namespace std;

void forward(string& data)
{
	for(auto& c : data)
	{
		if(c < 'a' || 'z' < c)
			continue;

		c++;
		if('z' < c)
			c -= 26;
	}
}

bool test(const string& data)
{
	if(data.find("the") != string::npos)
		return true;
	if(data.find("this") != string::npos)
		return true;
	if(data.find("that") != string::npos)
		return true;

	return false;
}

int main()
{
	while(!cin.eof())
	{
		char buffer[1024];
		cin.getline(buffer, 1024);
		string line(buffer);

		for(int i = 0; i < 26; i++)
		{
			if(test(line))
				break;
			forward(line);
		}

		cout << line;
	}

	return 0;
}

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

int main(void){
	
	char ango[1000],ttt[100];
	int leng,b;

	while(gets(ango)!=0){
		leng=strlen(ango);
		b=1;

		while(b){

			for(int i=leng-1;i>=0;i--){
				if(ango[i]>=97&&ango[i]<=122){
					ango[i]=ango[i]-1;
					if(ango[i]==96){
						ango[i]=122;
					}
				}
			}

			for(int i=0,j=0;i<=leng;i++,j++){
				if(ango[i]>=97&&ango[i]<=122&&i!=leng){
					ttt[j]=ango[i];
				}
				else{
					if((ttt[0]=='t'&&ttt[1]=='h'&&ttt[2]=='e'&&j==3)||(ttt[0]=='t'&&ttt[1]=='h'&&ttt[2]=='i'&&ttt[3]=='s'&&j==4)||(ttt[0]=='t'&&ttt[1]=='h'&&ttt[2]=='a'&&ttt[3]=='t'&&j==4)){
						b=0;
						break;
					}
					j=0;
				}
			}
		}
		printf("%s\n",ango);
	}
	return 0;
}

C++: #include <iostream>
#include <string>
//#include <string.h>
using namespace std;
int main(){
	char alpha[] = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";
	string str;
	while( 1 ){
		if( getline( cin, str ).eof() ) break;
		for( int a = 0; a < 26; a++ ){
			for( size_t i = 0; i < str.length(); i++ ){
				for( size_t j = 0; j < sizeof(alpha); j++ ){
					if( str[i] == alpha[j] ){
						str[i] = alpha[j + 1];
						break;
					}
				}
			}
		/*char word = strtok( str.c_str(), " " );
		if( word == "the" || word == "that" || word == "this" ) break;
		while( word == NULL ){
			word = strtok( NULL, ' ' );
			if( word == "the" || word == "that" || word == "this" ) goto end;
		}*/
			if( str.find("the") != string::npos || str.find("this") != string::npos || str.find("that") != string::npos ){
				break;
			}
		}
		cout << str << endl;
	}
}

C++: #include<iostream>
#include<string>
using namespace std;
int main()
{
	string key;
	
	while (getline(cin, key)) {

		for (int j = 0; j < 26; j++) {
			for (int i = 0; i < key.size(); i++) {
				if (key[i] >= 'a' && key[i] <= 'z') {
					key[i] = (key[i] == 'z') ? 'a' : key[i] + 1;
				}
			}

			if (key.find("the") != string::npos || key.find("this") != string::npos || key.find("that") != string::npos)
				cout << key<<endl;
		}
	}
	return 0;
}

C++: #include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<cassert>
#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<queue>
#include<set>
#include<map>
#include<utility>
#include<numeric>
#include<algorithm>
#include<bitset>
#include<complex>

using namespace std;

typedef long long Int;
typedef vector<int> vint;
typedef pair<int,int> pint;
#define mp make_pair

template<class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cout << *i << " "; cout << endl; }
template<class T> void chmin(T &t, T f) { if (t > f) t = f; }
template<class T> void chmax(T &t, T f) { if (t < f) t = f; }
int in() { int x; scanf("%d", &x); return x; }

int main() {
	string str;
	char chr[100];
	for(;gets(chr);){
		str=(string)(chr);
		int len=str.size();
		int i,c;
		for(c=1;c<=26;c++){
			for(i=0;i<len;i++){
				if('a'<=str[i]&&str[i]<='z'){
					str[i]++;
					if(str[i]>'z')str[i]='a';
				}
			}
			cout<<str<<endl;
			//if(str.find("the")!=string::npos||str.find("this")!=string::npos||str.find("that")!=string::npos){
				cout<<str<<endl;
				break;
			}
		}
	}
	return 0;
}