#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <math.h>

#define PREP(i, m, n) for(int i = m; i < n; i++)
#define MREP(i, m, n) for(int i = m - 1; i >= n; i--)

#define rep(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, b) for(int i = a; i < b; i++)
#define all(v) v.begin(), v.end()
#define rev(v) v.rbegin(), v.rend()
#define X first
#define Y second
#define MP make_pair
#define PB push_back

using namespace std;

map<int, char> number;

bool stringSearch(string input, string *after){
	for(int i = 0; i < 2; i++){
		if(input.find(after[i], 0) != string::npos){
			return true;
		}
	}
	return false;
}

void convert(string *after, string *key, int a, int b){
	for(int i = 0; i < 2; i++){
		for(int j = 0; j < key[i].size(); j++){
			after[i].push_back(number[(a * key[i][j] + b) % 26]);
		}
	}
}

void listConvert(map<char, char> &afterlist, int a, int b){
	for(int i = 0; i < 26; i++){
		afterlist[number[i]] = number[(a * number[i] + b) % 26];
	}
}

bool allSearch(string input, string *key){
	for(int a = 1; a < 26; a++){
		for(int b = 0; b < 26; b++){

			string after[2];
			map<char, char> afterlist;
			convert(after, key, a, b);
			listConvert(afterlist, a, b);

			if(stringSearch(input, after)){
				//文字があったら
				string answer;
				for(int i = 0; i < input.size(); i++){
					if(input[i] != ' '){
						for(map<char, char>::iterator it = afterlist.begin(); it != afterlist.end(); it++){
							if(it->second == input[i]) answer.push_back(it->first);
						}
					}
					else answer.push_back(' ');
				}
				cout << answer << endl;
				return true;
			}

		}
	}
	return false;
}

int main(){
	string key[] = {"this", "that"};
	number[0] = 'a';
	number[1] = 'b';
	number[2] = 'c';
	number[3] = 'd';
	number[4] = 'e';
	number[5] = 'f';
	number[6] = 'g';
	number[7] = 'h';
	number[8] = 'i';
	number[9] = 'j';
	number[10] = 'k';
	number[11] = 'l';
	number[12] = 'm';
	number[13] = 'n';
	number[14] = 'o';
	number[15] = 'p';
	number[16] = 'q';
	number[17] = 'r';
	number[18] = 's';
	number[19] = 't';
	number[20] = 'u';
	number[21] = 'v';
	number[22] = 'w';
	number[23] = 'x';
	number[24] = 'y';
	number[25] = 'z';
	
	int n = 0;
	cin >> n;
	while(n--){
		cin.ignore();
		string input;
		getline(cin, input);
		allSearch(input, key);
	}

	return 0;
}