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<cstdio>
#include<cmath>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<string>
#include<utility>
#include<algorithm>
#include<functional>
#include<deque>
#include<string.h>
#include<ctype.h>
#include<time.h>
#include<stdlib.h>
using namespace std;
 
char c[85];
 
bool search_th(){
  bool f = false;
  for (int i = 0; i < strlen(c); i++){
    if ((c[i] == 't' && c[i+1] == 'h' && c[i+2] == 'e') ||
        (c[i] == 't' && c[i+1] == 'h' && c[i+2] == 'i' && c[i+3] == 's') ||
        (c[i] == 't' && c[i+1] == 'h' && c[i+2] == 'a' && c[i+3] == 't')){
          f = true;  break;
    }
  }
  return f;
}
 
int main(){
  while (cin.getline(c, sizeof(c))){
    while (1){
      if (search_th() == true){
        cout << c << endl;
        break;
      }
      for (int j = 0; j < strlen(c); j++){
        if (c[j] >= 'a' && c[j] <= 'y') c[j]++;
        if (c[j] == 'z')                c[j] = 'a';
      }
    }
    for (int i = strlen(c); i < 85; i++){
      c[i] = '\0';
    }
  }
  return 0;
}

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

using namespace std;

#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define rep(i, j) FOR(i, 0, j)
#define repr(i, j) for(int i = j; i >= 0; --i)
#define INF (1 << 30)
#define MOD 1e9 + 7

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;

int main() {
	string s;
	string ans;
	bool flag = false;
	int key = 1;
	while(getline(cin, s)){ans += s;}
	while(1) {
		rep(i, ans.size()) {
			if(97 <= ans[i] && ans[i] <= 122) {
				int number = (ans[i] - 'a' + key) % 26;
				ans[i] = 'a' + number;
			}
		}
		string tmp;
		rep(i, ans.size()) {
			if(97 <= ans[i] && ans[i] <= 122) tmp += ans[i];
			else if(ans[i] == ' ') {
				if(tmp == "this" || tmp == "the" || tmp == "that") flag = true;
				else tmp.erase(tmp.begin(), tmp.end());
			}
		}
		if(flag) break;
	}
	cout << ans << endl;
	return 0;
}

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

std::string decrypto(std::string str) {
    using namespace std;
    regex pattern(".*(the|this|that).*");
    smatch sm;
    for (int c = 0; c < 'z' - 'a' + 1; ++c) {
        for (size_t i = 0; i < str.size(); ++i) {
            if ('a' <= str[i] && str[i] <= 'z') {
                if (str[i] == 'z') {
                    str[i] = 'a';
                } else {
                    str[i] += 1;
                }
            }
        }
        if (regex_match(str, sm, pattern)) {
            return str;
        }
    }
    return string("");
}

int main() {
    std::string str;
    while (std::getline(std::cin, str)) {
        std::cout << decrypto(str) << std::endl;
    }
}

C++: #include<iostream>
#include<cstdio>
#include<cmath>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<string>
#include<utility>
#include<algorithm>
#include<functional>
#include<deque>
#include<string.h>
#include<ctype.h>
#include<time.h>
#include<stdlib.h>
using namespace std;

char c[80], word[80][15];
int p = 0, q = 0;

bool search_th(){
  for (int i = 0; i <= p; i++){
    if (word[i][0] == 't' && word[i][1] == 'h'){
      if (word[i][2] == 'e' || (word[i][2] == 'i' && word[i][3] == 's') || (word[i][2] == 'a' && word[i][3] == 't')){
        return true;
      }
    }
  }
  return false;
}

void split_words(){
  for (int i = 0; i < 80; i++){
    for (int j = 0; j < 15; j++){
      word[i][j] = '\0';
    }
  }
  for (int i = 0; i < strlen(c); i++){
    if (c[i] >= 'a' && c[i] <= 'z'){
      word[p][q++] = c[i];
    } else {
      p++;
      word[p++][0] = c[i];
      q = 0;
    }
  }
  for (int i = 0; i <= p; i++){
    printf("word[%d]:%s\n", i, word[i]);
  }
}

int main(){
  while (cin.getline(c, sizeof(c))){
    p = 0;  q = 0;
    split_words();
    while (1){
      if (search_th() == true){
        for (int i = 0; i <= p; i++){
          cout << word[i];
        }
        puts("");  break;
      } else {
        for (int i = 0; i <= p; i++){
          for (int j = 0; j < strlen(word[i]); j++){
            if (word[i][j] >= 'a' && word[i][j] <= 'y') word[i][j]++;
            if (word[i][j] == 'z')                      word[i][j] = 'a';
          }
        }
      }
    }
    for (int i = 0; i < 80; i++){
      c[i] = '\0';
    }
  }
  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" };
	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 <cstdio>
#include <algorithm>
#include <stack>
#include <cmath>
using namespace std;

#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define llong long long

int main() {
  char a[80];
  REP(i,80) {
    if((a[i] = getc(stdin)) == EOF) break;
  }
  


  while(1) {
    int q = 0;//1..t, 2..th, 3..the, 4...thi, 5..this, 6..tha, 7..that 
    int j = 0;
    while(a[j] != EOF) {
      if(a[j] == 'z') a[j] = 'a';
      else if(a[j] >= 'a' && a[j] < 'z') a[j]++;
      j++;
    }
    j = 0;
    while(a[j] != EOF) {
      switch(q){
      case 0:
	if(a[j] == 't') q++;
	break;
      case 1:
	if(a[j] == 'h') q++;
	else q = 0;
	break;
      case 2:
	if(a[j] == 'e') q = 3;
	else if(a[j] == 'i') q = 4;
	else if(a[j] == 'a') q = 6;
	else q = 0;
	break;
      case 4:
	if(a[j] == 's') q = 5;
	else q = 0;
	break;
      case 6:
	if(a[j] == 't') q = 7;
	else q = 0;
	break;
      }
      j++;
    }
    if(q == 3 || q == 5 || q == 7) break;
  }
  
  int i = 0;
  while(a[i] != EOF) {
    printf("%c",a[i]);
    i++;
  }
  return 0;
}

C++: #include<string>
#include<vector>
#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<sstream>
#include<functional>
#include<map>
#include<stack>
#include<set>
#include<cmath>

#define REP(i,s,e) for(int i=int(s);i<=int(e);i++)
#define rep(i,n) for(int i=0;i<int(n);i++)

#define EPS 1e-6

using namespace std;

bool f(string a){

	string::size_type p=a.find("the");
	string::size_type q=a.find("this");
	string::size_type r=a.find("that");
	if(p!=string::npos || q!=string::npos || r!=string::npos)
	return true;
	else return false;

	}

int main(){

   string s,s1;

   while(getline(cin,s)){



	int n=s.size();

	REP(k,1,26){
	s1=s;
	rep(i,n){
	if('a'<=s1[i] && s1[i]<='a'-1+k) s1[i]+=26-k;
	if('a'+k<=s1[i] && s1[i]<='z') s1[i]+=-k;
	}

	if(f(s1)){ cout << s1 << endl; break; }

	}


	}


    return 0;
}