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;
int main(){
  string str[80];
  vector<int> num;
  //while(cin>>str[i]){
  for(int i=0;i<10;i++){
    cin>>str[i];
    if(str[i].size()==4||str[i].size()==3)
      num.push_back((str[i].size()*100)+i);
  }
  int flag=0,zure=0;
  for(int i=0;i<num.size();i++){
    if(num[i]/100==3){
      for(int j=0;j<3;j++){
	for(int k=1;k<26;k++){
	  if(str[num[i]-300][0]=='t'+k){
	    if(str[num[i]-300][1]=='h'+k&&str[num[i]-300][2]=='e'+k){
	      zure=k;flag=1;break;
	    }
	  }
	}
	if(flag==1)
	  break;
      }
      if(flag==1)
	break;
    }
    else{
      for(int j=0;j<4;j++){
	for(int k=1;k<26;k++){
	  if(str[num[i]-400][0]=='t'+k&&str[num[i]-400][1]=='h'+k){
	    if(str[num[i]-400][2]=='i'+k&&str[num[i]-400][3]=='s'+k||str[num[i]-400][2]=='a'+k&&str[num[i]-400][2]=='t'+k){
	      zure=k;flag=1;break;
	    }
	  }
	}
	if(flag==1)
	  break;
      }
      if(flag==1)
	break;
    }
  }
  for(int j=0;j<10;j++){
    for(int k=0;k<str[j].size();k++){
      str[j][k]=str[j][k]+zure;
    }
  }
  for(int j=0;j<10;j++){
    cout<<str[j];
    if(j!=10)
      cout<<" ";
  }cout<<endl;
  return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
void slide(string& s) {
  for (auto& c: s)
    if (c == 'a') c = 'z';
    else if (c != '.' && c != ' ') c -= 1;
}
bool check(const string& s) {
  if (s.find("the") == string::npos) return true;
  if (s.find("this") == string::npos) return true;
  if (s.find("that") == string::npos) return true;
  return false;
}
int main() {
  string line;
  while(getline(cin, line)) {
    while(check(line))
      slide(line);
    cout << line << endl;
  }
}

C++: //include
 //------------------------------------------
 #include <vector>
 #include <list>
 #include <map>
 #include <set>
 #include <deque>
 #include <stack>
 #include <bitset>
 #include <algorithm>
 #include <functional>
 #include <numeric>
 #include <utility>
 #include <sstream>
 #include <iostream>
 #include <iomanip>
 #include <cstdio>
 #include <cmath>
 #include <cstdlib>
 #include <cctype>
 #include <string>
 #include <cstring>
 #include <ctime>

 using namespace std;

 //conversion
 //------------------------------------------
 inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
 template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

 //math
 //-------------------------------------------
 template<class T> inline T sqr(T x) {return x*x;}

 //typedef
 //------------------------------------------
 typedef vector<int> VI;
 typedef vector<VI> VVI;
 typedef vector<string> VS;
 typedef pair<int, int> PII;
 typedef long long LL;
 typedef unsigned long long ULL;

 //container util
 //------------------------------------------
 #define ALL(a)  (a).begin(),(a).end()
 #define RALL(a) (a).rbegin(), (a).rend()
 #define PB push_back
 #define MP make_pair
 #define SZ(a) int((a).size())
 #define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
 #define EXIST(s,e) ((s).find(e)!=(s).end())
 #define SORT(c) sort((c).begin(),(c).end())

 //repetition
 //------------------------------------------
 #define FOR(i,a,b) for(int i=(a);i<(b);++i)
 #define REP(i,n)  FOR(i,0,n)

 //constant
 //--------------------------------------------
 const double EPS = 1e-10;
 const double PI  = acos(-1.0);

 //clear memory
 #define CLR(a) memset((a), 0 ,sizeof(a))

 //debug
 #define dump(x)  cerr << #x << " = " << (x) << endl;
 #define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

 int main() {
   int n;
   string str;

   while(getline(cin, str)) {
     for(int i = 0; i < str.size(); i++) {
       for(int j = 0; str[i]+j <= 'z'; j++) {
	 if(str[i] + j == 't' && str[i+1] + j == 'h') {
	   n = j;
	   break;
	 }
       } 
       for(int j = 0; str[i]-j >= 'a'; j++) {
	 if(str[i] - j == 't' && str[i+1] - j == 'h') {
	   n = -j;
	 break;
	 }
       }
     }
     
     for(int i = 0; i < str.size(); i++) {
       if(str[i] == ' ' || str[i] == '.' || str[i] == '\n') printf("%c", str[i]);
       else printf("%c", str[i]+n);
     }
     cout << endl;
   }
 }

C++: #include <stdio.h>
#include <math.h>
#include <ctype.h>

char buf[128];

int main(void)
{
	int i, j, flag = 0;
	scanf("%[^\n]s", buf);
	
	for (i = 'a'; i <= 'z' && flag == 0; i++){
		//check
		for (j = 0; j < 80; j++){
			if (buf[j] == 't' && buf[j + 1] == 'h'){
				if ((buf[j + 2] == 'i' && buf[j + 3] == 's') || (buf[j + 2] == 'a' && buf[j + 3] == 't') || (buf[j+2]=='e')){
					//this	that	the
					flag = 1;
				}
			}
		}

		//add 1
		if (flag == 0){
			for (j = 0; j < 80; j++){
				if (isalpha(buf[j])){
					if (buf[j] == 'z'){
						buf[j] = 'a';
					}
					else{
						buf[j]++;
					}
				}
			}
		}
	}

	for (i = 0; i < 80; i++){
		printf("%c\n", buf[i]);
	}
	return 0;
}

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

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
#define ALL(a)  (a).begin(),(a).end()
#define REP(i,n) for(int i=0;i<(n);++i)
const double EPS = 1e-10;
const double PI  = acos(-1.0);
#define dump(x) cerr << "  (L" << __LINE__ << ") " << #x << " = " << (x) << endl;
#define dumpv(x) cerr << "  (L" << __LINE__ << ") " << #x << " = "; REP(q,(x).size()) cerr << (x)[q] << " "; cerr << endl;
template<typename T1, typename T2>
ostream& operator<<(ostream& s, const pair<T1, T2>& d) {return s << "(" << d.first << "," << d.second << ")";}


int main() {
  string s;
  while (getline(cin, s)) {
    string orig;
    for (int i = 1; i <= 'z'-'a'; i++) {
      orig = s;
      for (int j = 0; j < orig.size(); j++) {
        if (orig[j] >= 'a' && orig[j] <= 'z') {
          orig[j] = 'a' + ((orig[j]-'a') + i) % ('z'-'a'+1);
        }
      }
      if (orig.find("the") != string::npos ||
          orig.find("this") != string::npos ||
          orig.find("that") != string::npos) {
        break;
      }
    }
    cout << orig << endl;
  }
}

C++: #include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
int main()
{
	char s[80];
	char str1[] = "this";
	char str2[] = "that";
	char str3[] = "the";

	while(scanf("%s",s) != EOF){

		int len = strlen(s);

		for(int i = 0;i < 26;i++){
			for(int j = 0;j < len;j++){

				if(s[j] != '.' && s[j] != ' ' && s[j] != '\n'){	
					if(s[j] + i > 122){
						s[j] -= 26-i;
					}

					else {
						s[j] += i;
					}
				}
			}

			if(strstr(s,str1) != NULL){
				cout << s << endl;
				break;
			}

			if(strstr(s,str2) != NULL){
				cout << s << endl;
				break;
			}

			if(strstr(s,str3) != NULL){
				cout << s << endl;
				break;
			}
		}
	}
}