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 <cstdio>
#include <stdio.h>
#include <string>

using namespace std;
static const int MAXV = 81;

bool hantei(char* data);
void irekae(char* data);

int main() {
  while(!feof(stdin)) {
    char data[MAXV];
    if(fgets(data, sizeof(data), stdin)==NULL) break;
    while(!hantei(data))
      irekae(data);
    printf("%s", data);
  }
}

bool hantei(char* data) {
  if(strstr(data, "the")) return 1;
  if(strstr(data, "this")) return 1;
  if(strstr(data, "that")) return 1;
  return 0;
}

void irekae(char* data) {
  for(int i=0;data[i]!=0;i++) {
    if(data[i]>='a' && data[i]<='z') {
      if(data[i]=='z')data[i]='a';
      else data[i]++;
    }
  }
}

C++: #include <bits/stdc++.h>
#include <vector>
using namespace std;
string str;	
int a, b, c, d;
int main(){
	while(getline(cin, str)){
		a = str.length();
		for(int i = 0; i < a; i++){
			if(str[i] < 97 || str[i] > 122){
				cout << str[i];
			}
			else {
				b = (int)str[i];
				b = b - 4;
				if(b < 97)
					b = b + 26;
				cout << (char)b;
			}
		}
		cout << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <list>
#include <algorithm>
#include <cmath>
#include <stack>
#include <set>
using namespace std;

#define REP(i,n) for(int (i)=0; (i)<(n); (i)++)
#define FOR(i,a,b) for(int (i)=(a); (i)<(b); (i)++)
#define PUSH(n,v) for(int i=0; i<(n); i++) {int j; cin >> j; v.push_back(j);}
#define ALL(v) v.begin(), v.end()

void rot1(string &s) {
    string t = "";
    REP(i,s.size()) {
        if (s[i] > 'a' && s[i] < 'z') {
            if (s[i] == 'a') t += "z";
            else t += s[i] - 1;
        }else {
            t += s[i];
        }
    }
    s = t;
}

int main() {
    string s;
    while(getline(cin, s)) {
        while(s.find("the") == string::npos && s.find("this") == string::npos && s.find("that") == string::npos) {
            rot1(s);
        }
        cout << s << endl;
    }
    return 0;
}

C++: 
#include <cmath>
#include <iostream>
#include <cstdio>
#include <ctype.h>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <iomanip>
#include <set>
#include <stack>
#include <queue>
#include <vector>
#include <sstream>


using namespace std;



string shift_str(string str, int num)
{
	int ascii;
	string ret;
	
	for (int i=0; i<str.length(); i++)
	{
		ascii = (int)str[i];
		//cout << "ascii = " << ascii << endl;
		
		if (!('a' <= ascii && ascii <= 'z'))
		{
			ret += ascii;
		} else {
			ascii += num;
			if (ascii > 'z')
			{
				ret += ((ascii - 'z') + 'a' - 1);
			} else {
				ret += ascii;
			}
		}
		
	}
	
	return ret;
}
//the this that


int main()
{
	string str;
	string ret;
	
	while (getline(cin, str))
	{
		for (int i=1; i<=26; i++)
		{
			ret = shift_str(str, i);
			if ( ret.find("the", 0) != string::npos
				|| ret.find("this", 0) != string::npos
				|| ret.find("that", 0) != string::npos )
			{
				//cout << "i = " << i << endl;
				cout << ret << endl;
				break;
			}
		}
	}
	
	return 0;
}

C++: #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)) {
    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;
	}
    return 0;
	}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <istream>
#include <sstream>
#include <iomanip>
#include <iterator>
#include <climits>
using namespace std;

typedef ostringstream OSS;
typedef istringstream ISS;

typedef vector<int> VI;
typedef vector< VI > VVI;

typedef long long LL;

typedef pair<int, int> PII;
typedef vector<PII> VPII;

#define X first
#define Y second

string nextConvert(string s) {
	transform(s.begin(), s.end(), s.begin(), [](char c)->char{
			if (islower(c)) return (c - 'a' + 1) % 26 + 'a';
			if (isupper(c)) return (c - 'A' + 1) % 26 + 'A';
			else 			return c;
		});
	return s;
}

bool check(string s) {
	vector<string> targets({"the", "this", "that"});

	for (auto &target : targets) {
		if (s.find(target) == string::npos) {
			return false;
		}
	}

	return true;
}

int main(void) {
	string s;

	while (getline(cin, s)) {
		for (int i = 0; i < 26; i++) {
			s = nextConvert(s);
			if (check(s)) {
				cout << s << endl;
				break;
			}
		}
	}

	return 0;
}

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

int main(){
	string str[100];
	int k = 0;
	int zure[100];
	bool flag[100] = {false};
	while(getline(cin, str[k])){
		for(int j = 0; j < 26; j++){
			for(int i = 0; i < str[k].size()-2; i++){
				if(str[k][i] == 't'+j && str[k][i+1] == 'h'+j && str[k][i+2] == 'e'+j){
					zure[k] = j;
					flag[k] = true;
					break;
				}
			}
			if(flag[k] == true){
				k++;
				break;
			}
			for(int i = 0; i < str[k].size()-3; i++){
				if(str[k][i] == 't'+j && str[k][i+1] == 'h'+j && str[k][i+2] == 'i'+j && str[k][i+3] == 's'+j){
					zure[k] = j;
					flag[k] = true;
					break;
				}
			}
			if(flag[k] == true){
				k++;
				break;
			}
			for(int i = 0; i < str[k].size()-3; i++){
				if(str[k][i] == 't'+j && str[k][i+1] == 'h'+j && str[k][i+2] == 'a'+j && str[k][i+3] == 't'+j){
					zure[k] = j;
					flag[k] = true;
					break;
				}
			}
			if(flag[k] == true){
				k++;
				break;
			}
		}
		k++;
	}
	for(int j = 0; j < k; j++){
		for(int i = 0; i < str[j].size(); i++){
			if(str[j][i] >= 'a' && str[j][i] <= 'z'){
				str[j][i] = str[j][i]-zure[j];
				if(str[j][i] < 'a'){
					str[j][i] = str[j][i]+26;
				}
				cout << str[j][i];
			}
			else{
				cout << str[j][i];
			}
		}
		cout << endl;
	}
}