Go: package main

import (
	"bufio"
	"os"
	"strings"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func cipher(text string, direction int, int_shift int) string {
	shift, offset := rune(int_shift), rune(26)
	runes := []rune(text)
	for index, char := range runes {
		switch direction {
		case 1:
			if char >= 'a' && char <= 'z'-shift || char >= 'A' && char <= 'Z'-shift {
				char = char + shift
			} else if char > 'z'-shift && char <= 'z' || char > 'Z'-shift && char <= 'Z' {
				char = char + shift - offset
			}
		case -1:
			if char >= 'a'+shift && char <= 'z' || char >= 'A'+shift && char <= 'Z' {
				char = char - shift
			} else if char >= 'a' && char < 'a'+shift || char >= 'A' && char < 'A'+shift {
				char = char - shift + offset
			}
		}
		runes[index] = char
	}
	return string(runes)
}

func main() {
	for scanner.Scan() {
		infos := strings.Split(scanner.Text(), " ")
		plain := make([]string, len(infos))
		// fmt.Println(infos)
		Decryption:
			for i := 0; i < 26; i++ {
				for j := range infos {
					plain[j] = cipher(infos[j], 1, i)
				}
				for j := range plain {
					if plain[j] == "this" || plain[j] == "that" || plain[j] == "the" {
						break Decryption
					}
				}
			}
			fmt.Println(strings.Join(plain, " "))
	}
}

C++: #include <fstream>
#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
using namespace std;

char shift(char c, int n) {
  if (c >= 'a' && c <= 'z')
    return (c + n <= 'z') ? c + n : 'a' + (c + n - 'z' - 1);
  else
    return c;
}

bool exist(string str, string c) {
  return str.find(c, 0) != string::npos;
}

int main() {
  // ifstream cin("../test.txt");
  vector<string> _the(26);
  vector<string> _this(26);
  vector<string> _that(26);
  _the[0] = "the";
  _this[0] = "this";
  _that[0] = "that";
  for (int i = 1; i < 26; i++) {
    for (int j = 0; j < 3; j++) {
      _the[i] += shift(_the[0][j], i);
    }
    for (int j = 0; j < 4; j++) {
      _this[i] += shift(_this[0][j], i);
      _that[i] += shift(_that[0][j], i);
    }
  }

  string str, nstr;
  while (getline(cin, str)) {
    for (int i = 1; i < 26; i++) {
      if ( exist(str, _the[i]) || exist(str, _this[i]) || exist(str, _that[i])) {
        nstr = "";
        int len = str.length();
        for (int j = 0; j < len; j++) {
          nstr += shift(str.at(j), 26 - i);
        }
        break;
      }
    }

    cout << nstr << endl;
  }
}

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

using namespace std;

void solve()
{
	string str;
	getline(cin, str);
	string word;
	int n = str.size();
	for(int j = 1; j < 26; ++j)
	{
		word.clear();
		for(int i = 0; i < n; ++i)
		{
			if('a' <= str[i] && str[i] <= 'z')
			{
				word += (str[i] + j -'a') % 26 + 'a';
			}
			else
			{
				word += str[i];
			}
		}
		if(word.find("this") != -1 && word.find("the") != -1 && word.find("that") != -1)
		{
			cout << word << endl;
		}
	}
}

int main()
{
	solve();
	return(0);
}

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

bool islower(char a){
	if(a>='a' && a<='z') return true;
	else return false;
}

int main(){
	string s,ans;
	while(getline(cin,s)){
		int shift=1;
		ans=s;
		while(1){
			if(ans.find("the" ,0)!=string::npos || ans.find("this",0)!=string::npos || ans.find("that",0)!=string::npos) break;
			for(int i=0;i<s.size();++i){
				if(islower(s[i])){
					if(s[i]+shift<='z'){
						ans[i]=s[i]+shift;
					} else {
						ans[i]=s[i]-26+shift;
					}
				}
			}
			shift++;
		}
		cout << ans << endl;
	}
	return 0; 
}

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

using namespace std;

int main() {
	string str;
	string in;
	vector<string> s;
	while (cin >> in) s.push_back(in);
	for (int i=0; i<(int)s.size(); i++) {
		str += s[i];
		if (i<(int)s.size()-1) str += " ";
	}
	
	for (int i=0; i<26; i++) {
		for (int j=0; j<(int)str.size(); j++) {
			if (str[j] == '.' || str[j] == ' ') continue;
			str[j] = str[j] + i;
			if (str[j] >= 'z') str[j] = 'a' + str[j] - 'z';
		}
		if (str.find("the")!=str.npos || str.find("this")!=str.npos || str.find("that")!=str.npos) break;
	}
	
	cout << str << 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)) {
    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 <stdio.h>

int main(void)
{
	char str[100];
	int num, num2;
	int i;
	
	while (fgets(str, 100, stdin) != NULL){
		num = 't' - str[0];
		i = 0;
		while (str[i] != '\0'){
			if (str[i] >= 'a' && str[i] <= 'z'){
				str[i] += num;
				if (str[i] > 'z'){
					num2 = str[i] - 'z';
					str[i] = num2 + 'a';
				}
				else if (str[i] < 'a'){
					num2 = 'a' - str[i];
					str[i] = 'z' - num2;
				}
			}
			i++;
		}
		printf("%s", str);
	}
	
	printf("\n");
	
	return (0);
}

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

// determine whether it is "the","this" or "that"
char get_shift(string w) {
	char sh = 't' - w.front();
	for_each(w.begin(),w.end(),[sh](char &c) {
		c += sh;
		if (c > 'z') {
			c -= (char)26;
		} else if (c < 'a') {
			c += (char)26;
		}
	});
	if (w.find("the") == string::npos && w.find("this") == string::npos && w.find("that") == string::npos) {
		sh = '\0';
	}
	return sh;
}

int main() {
	string s;
	while (getline(cin,s)) {
		istringstream stream(s);
		string w;
		char sh;
		while (stream >> w) {
			while (!w.empty() && w.front() == '.') {
				w.erase(0,1);
			}
			while (!w.empty() && w.back() == '.') {
				w.pop_back();
			}
			if (!w.empty()) {
				if ((sh = get_shift(w)) != '\0') {
					break;
				}
			}
		}
		for_each(s.begin(),s.end(),[sh](char &c) {
			if (c >= 'a' && c <= 'z') {
				c += sh;
				if (c > 'z') {
					c -= (char)26;
				} else if (c < 'a') {
					c += (char)26;
				}
			}
		});
		cout << s << endl;
	}
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <stack>
#include <vector>


int main()
{
	char s[81];
	while (fgets(s, 81, stdin) != NULL)
	{
		for (int i = 0; i < 26; ++i)
		{
			char decoded[81];
			for (int j = 0; s[j] != '\0'; ++j)
				decoded[j] = islower(s[j]) ? 'a'+(s[j]-'a'+i)%26 : s[j];
			decoded[strlen(s)] = '\0';
			if (strstr(decoded, "the")
				|| strstr(decoded, "this")
				|| strstr(decoded, "that"))
			{
				puts(decoded);
				break;
			}
		}
	}
	return 0;
}