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 <stdio.h>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <stdlib.h>
#include <vector>

using namespace std;


int main(){

	vector<string> str, ans;
	string temp;
	int slide;

	while(cin >> temp){
		str.push_back(temp);
	}

	for(int i=0 ; i<str.size() ; i++){
		ans.push_back(str[i]);
	}

	for(int i=0 ; i<25 ; i++){

		for(int j=0 ; j<str.size()-1 ; j++){
			for(int k=0 ; k<str[j].size() ; k++){
				str[j][k]++;
				if(str[j][k] > 'z'){
					str[j][k] = str[j][k] - 'z' + 'a' -1;
				}
			}
		}

		for(int k=0 ; k<str[str.size()-1].size()-1 ; k++){
			str[str.size()-1][k]++;
			if(str[str.size()-1][k] > 'z'){
				str[str.size()-1][k] = str[str.size()-1][k] - 'z' + 'a' -1;
			}
		}
		for(int k=0 ; k<str.size() ; k++){
			if(str[k] == "the" || str[k] == "that" || str[k] == "this"){
				slide = i;
				break;
			}
		}
	}

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

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

	return 0;
}

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

//メイン関数
int main()
{
  char str[81];
   while(fgets(str,sizeof(str),stdin)!=NULL){
  // while(scanf("%[^/n]s",str)!=EOF){

    //strstrで探索
  if((strstr(str,"the")) || (strstr(str,"this")) || (strstr(str,"that"))){
    puts(str);
    continue;
  }
  int len=strlen(str);
    for(int i=1;i<=26;i++){
      for(int j=0;j<len;j++){
	if(str[j]>='a' && str[j]<='z'){       
	  str[j]++;
	  if(str[j]=='{'){
	    str[j]='a';
	  }
	}
      }
      //strstrで探索
      if((strstr(str,"the")) || (strstr(str,"this")) || (strstr(str,"that")))break;
    }
    printf("%s",str);
  }
}

C++: #include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
int main(){

    char a[100];
    while(scanf("%[^\n]",a) != EOF){
        bool flg = 0;
        for(int i = 1; i < 26; i++){
            unsigned char ans[100] = {0};
            for(int j = 0; j < strlen(a); j++){
                if(a[j] == ' ' || a[j] == '.') ans[j] = a[j];
                else ans[j] = a[j] + i;
                if(ans[j] > 'z') ans[j] -= 26;
            }
            for(int j = 0; j < strlen(a); j++){
                if(ans[j] == 't' && ans[j+1] == 'h'){
                    if(ans[j+2] == 'e' && ans[j+3] == ' ')flg = 1;
                    if(ans[j+2] == 'i' && ans[j+3] == 's' && ans[j+4] == ' ')flg = 1;
                    if(ans[j+2] == 'a' && ans[j+3] == 't' && ans[j+4] == ' ')flg = 1;
                }
                if(flg){
                    if(j == 0){
                        cout << ans << endl;
                        goto end;
                    }
                    else{
                        if(ans[j-1] == ' '){
                            cout << ans << endl;
                            goto end;
                        }
                    }
                }
            }
        }
        end:;
        fflush(stdin);
    }

    return 0;
}

C++: #include <cctype>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;

bool includes_keyword(const char *str) {
  const static char *keywords[] = { "the", "this", "that" };
  for (const auto keyword : keywords) {
    const char *pos = strstr(str, keyword);
    if (pos == NULL) { continue; }
    if (pos != str && isalpha(pos[-1])) { continue; }
    if (isalpha(pos[strlen(keyword)])) { continue; }
    return true;
  }
  return false;
}

int main() {
  char *cipher = NULL;
  size_t buffer_size = 0;
  ssize_t len;
  while ((len = getline(&cipher, &buffer_size, stdin)) > 0) {
    if (cipher[len - 1] == '\n') {
      cipher[len - 1] = '\0';
      len -= 1;
    }

    char c = 'z';
    for (int i = 0; i < len; ++i) {
      if (isalpha(cipher[i]) && c > cipher[i]) { c = cipher[i]; }
    }
    int shift_begin = 'a' - c;
    int shift_end = shift_begin + 26;
    char decoded[81];
    for (int shift = shift_begin; shift < shift_end; ++shift) {
      strcpy(decoded, cipher);
      for (int i = 0; i < len; ++i) {
        if (isalpha(decoded[i])) { decoded[i] += shift; }
      }
      if (includes_keyword(decoded)) {
        puts(decoded);
        break;
      }
    }
  }

  free(cipher);

  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
using namespace std;
int main(){
  string s;
  int pl=0;
  getline(cin,s);
  for(int i =-30;i<30;i++){
    for(int j = 0; j < s.size(); j++){
      if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'e'){
	pl = i;
	break;
      }
      else if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'a' && s[j+3]+i=='t'){
	pl = i;
	break;
      }
      else if(s[j]+i=='t' &&s[j+1]+i == 'h' && s[j+2]+i == 'i' && s[j+3]+i=='s'){
	pl = i;
	break;
      }
    }
    if(pl!=0) break;
  }
  for(int i=0;i <s.size();i++){
    if(s[i]<='z' && s[i]>='a') s[i] += pl;
  }
  cout<<s<<endl;
}

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

int main(){
	
	string str, str1;

	while(getline(cin, str)){
		for(int i=0; i<26; i++){
			for(int j=0; j<str.length(); j++){
				if(str[j] == ' ' || str[j] == '.') continue;
				if(str[j] == 'z') str[j] = 'a';
				else{
					str[j]++;
				}
			}
			
			str1 = "";
			for(int j=0; j<str.length(); j++){
				if(str[j] != ' ' && str[j] != '.') str1 += str[j];
				else{
					if(str1 == "the" || str1 == "this" || str1 == "that"){
						cout << str << endl;
						return 0;
					}
					else str1 = "";
				}
			}
		}
	}

	return 0;
	
}

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

using namespace std;

#define REP(i,a,b) for((i)=(a);(i)<(int)(b);(i)++)
#define rep(i,n) REP(i,0,n)
// BEGIN CUT HERE
#define foreach(itr,c) for(typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)
template<class T> inline string toString(T x){ostringstream sout;sout<<x;return sout.str();}
// END CUT HERE

int main(){
  int i, j;
  string str;
  vector<string> data;

  while(cin >> str) data.push_back(str);
  data[data.size()-1].erase(data[data.size()-1].size()-1);

  while(1){
    rep(i,data.size()) rep(j,data[i].size()) data[i][j]--;
    rep(i,data.size()){
      if(data[i] == "this" || data[i] == "the" || data[i] == "that"){
        rep(j,data.size()){
          if(j == data.size()-1) cout << data[j] << "." << endl;
          else cout << data[j] << " ";
        }
        return 0;
      }
    }
  }

  return 0;
}