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 <iostream>
#include <algorithm>
#include <sstream>

using namespace std;

bool is_comprehensible(const string& str){
	istringstream iss(str);
	string word;
	while(iss >> word){
		if(word == "the" || word == "this" || word == "that"){
			return true;
		}
	}
	return false;
}

string shift_string(const string& str, char n){
	string result;
	for(auto& v: str){
		if('a' <= v && v <= 'z'){
			result += (v - 'a' + n) % 26 + 'a';
		}
		else{
			result += v;
		}
	}
	return result;
}

int main(){
	string str;
	while(getline(cin, str)){
		for(int i = 0; i < 26; ++i){
			auto shifted = shift_string(str, i);
			if(is_comprehensible(shifted)){
				cout << shifted << endl;
				break;
			}
		}
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define int long long
#define ll long long
#define rep(i,n) for(int i=0;i<n;i++)
#define INF (((ll)1<<31)-1)
#define eps LDBL_EPSILON
#define moder (1000000007)
#define pie 3.141592653589793238462643383279
#define P std::pair<int,int>
#define prique priority_queue
#define ggr getchar();getchar();return 0;
using namespace std;
signed main(){
    string s;
    while(getline(cin,s)){
        rep(i,26){
            bool flag=false;
            string t="";
            rep(j,s.size()){
                if(isalpha(s[j]))t=t+(char)('a'+(s[j]-'a'+i)%26);
                if(s[j]==' '){
                    if(t=="the"||t=="this"||t=="that"){
                        flag=true;
                        break;
                    }
                    t="";
                }
            }
            if(flag){
                rep(j,s.size()){
                    if(isalpha(s[j]))cout<<(char)('a'+(s[j]-'a'+i)%26);
                    else cout<<s[j];
                }
                cout<<endl;
                goto kaage;
            }
        }
        kaage:;
    }
    ggr;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
  string str;
  getline(cin,str);
  
  for(int i=0;i<str.size();i++){
    
    if(str[i] >= 'a' && str[i] <= 'z'){
      int a = (26+(str[i]-'a'-4))%26;
      str[i] = ('a'+a);
    }
    cout << str[i];
  }
  cout << endl;
  return (0);
}

C++: #include <bits/stdc++.h>
using namespace std;
//????????????????????????????????????
void Check(const string& str){
  string strparent=str;
  int gap=1;
  while(strparent.find("the")==(string::npos)&&
        strparent.find("this")==(string::npos)&&
        strparent.find("that")==(string::npos)){
    for(int i=0;i<str.length();i++){
      if(!isalpha(str[i]))continue;//" "
      //strparent[i]=(gap+str[i]-'a')%26+'a';
      strparent[i]=(gap+str[i])%26+'a';
    }
    gap++;
  }
  cout<<strparent<<endl;
}

int main(){
  string str;
  while(getline(cin,str)){
    Check(str);
  }
}

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

using namespace std;


int main(){
	string line;

	while(getline(cin, line)){
		int flag;
		for(int i=0 ; i<26 ; i++){
			for(int j=0 ; j<line.size() ; j++){
				if(line[j] != ' ' && line[j] != '.'){
					if((line[j]-1) < 'a'){
						line[j] = line[j] -'a' + 'z' -1;
					}else{
						line[j]--;
					}
				}
			}

			for(int k=0 ; k<line.size() ; k++){
				if(line[k] == 't' && line[k+1] == 'h'){
					flag = 1;
					break;
				}
			}
			if(flag == 1) break;
		}

		cout << line << endl;
	}
	return 0;
}

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

int main() {
	string st;
	string w[3]={"the","this","that"};
	int wn[3]={3,4,4},k,i,j,s,f;
	while(getline(cin,st)) {
    cout << st.size() << endl;
    k=0;
	while(k<st.size()) {
		for (i=0;i<3;i++) {
			s=0; f=0;
			if (st.size()<k+wn[i]) break;
			for (j=0;j<wn[i]-1;j++) if ((w[i][j]-w[i][j+1])==(st[k+j]-st[k+j+1])) s++;
			if (s==wn[i]-1) { f=1; i=5; }
		}
		if (f==1) break;
		k++;
		}
	if (f==0) cout << st; else {
	for (i=0;i<st.size();i++) if ((st[i]>='a' && st[i]<='z')) cout << (char)(st[i]-(st[k]-'t')) ; else cout << st[i];
	}	
	cout << endl;
	}

C++: #include <stdio.h>
#include <string.h>
int main()
{
char str[81];
int i,j,l;
while(fgets(str,sizeof(str),stdin) != NULL){
l = strlen(str);
for(i = 0; i < 26; i++){
if(strstr(str,"the") != '\0' || strstr(str,"this") != '\0' || strstr(str, "that") != '\0')
break;
else{
for(j = 0; j < l; j++){
if(('a' <= str[j] && str[j] <= 'y') || ('A' <= str[j] && str[j] <= 'Y'))
str[j]++;
else if(str[j] == 'z')
str[j] = 'a';
else if(str[j] == 'Z')
str[j] = 'A';
}
}
}
printf("%s", str);
}
return 0;
}

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

int main(){
   string str;
   bool ans=false;
   getline(cin,str);
   
   string::iterator ite=str.begin();
   
   while(1){
      //cout << str.find("the");
      if(str.find("the")<str.size()) ans=true;
      else if(str.find("this")<str.size()) ans=true;
      else if(str.find("that")<str.size()) ans=true;
      if(ans) break;
      for(int i=0;i<str.size();i++){
         if(*(ite+i)>='A'&&*(ite+i)<='z') *(ite+i)-=1;
      }
   }
   cout << str << endl;
}

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

bool is_valid(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;
	}
	return false;
}

int main() {
	std::string str;
	std::getline(std::cin, str);
	
	std::string ans;
	const int limit = 'z' - 'a' + 1;
	for (int i = 0; i < limit; ++i) {
		for (auto c : str) {
			int elem = c + i;
			if (c >= 'a' && c <= 'z') {
				if (elem > 'z') {
					elem = 'a' + elem - ('z' + 1);
				}
				ans.push_back(elem);
			} else {
				ans.push_back(c);
			}
		}
		if (is_valid(ans)) {
			break;
		}
		ans.clear();
	}
	
	std::cout << ans << std::endl;
}

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

using namespace std;

int main(void){
	int i, len;
	string encrypted, tmp, decoded;

	getline(cin, encrypted);
	len = encrypted.size();

	while(encrypted.find("this") == string::npos ||
		  encrypted.find("that") == string::npos ||
		  encrypted.find("the")  == string::npos){
		for(i=0;i<len;i++){
			if(encrypted[i] >= 97 && encrypted[i] <=122){ //isAlphabet(encrypted[i]);
				encrypted[i] += 1;
				if(encrypted[i] == 123) encrypted[i] = 97;//z->a
			}
		}
	}

	cout << encrypted << endl;

	return 0;
}