#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;

typedef long long ll;
typedef vector<int> vint;
typedef vector<long long> vll;
typedef pair<int,int> pint;
typedef pair<long long, long long> pll;

#define MP make_pair
#define PB push_back
#define ALL(s) (s).begin(),(s).end()
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P) 
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P) 
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P) 
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }



string tostr(char s[], int a, int n) {
    string res = "";
    for (int i = a; i < a+n; ++i) {
        if (s[i] != 0) res += s[i];
    }
    return res;
}




int n;

string solve(string str) {
	for (int i = 1; i < 26; ++i) {
		if (i % 2 == 0) continue;
		if (i % 13 == 0) continue;
		for (int j = 0; j < 26; ++j) {
			string next = "";
			for (int k = 0; k < str.size(); ++k) {
				if (str[k] == ' ') next += " ";
				else {
					int is = str[k] - 'a';
					int in = (is * i + j) % 26;
					char cn = 'a' + in;
					next += cn;
				}
			}

			bool con = false;
			for (int k = 0; k < next.size()-3; ++k) {
				string sub = next.substr(k, 4);
				if (sub == "this" || sub == "that") {
					con = true;
					break;
				}
			}
			if (con) {
				return next;
			}
		}
	}
	return str;
}



int main() {
	cin >> n; cin.ignore();
	string str;
	for (int i = 0; i < n; ++i) {
		getline(cin, str);
		//str = "y eazqyp pnop pngtg ye obmpngt xmybp mr lygw";
        cout << solve(str) << endl;
    }
    
    return 0;
}
