#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define pb push_back
#define mp make_pair
#define ERASE(v,i) (v).erase(remove(all(v),i),(v).end())
#define rep(i,n) for(int i=0;i<(int)n;++i)
#define each(it,c) for(typeof((c).begin()) it=(c).begin();it!=(c).end();++it)
#define debug(x) cerr<<#x<<" = "<<(x)<<endl;
#define LINE cerr<<"LINE: "<<__LINE__<<endl;
inline int toInt(string s){int v;istringstream i(s);i>>v;return v;}
template<class T> inline string toString(T x){ostringstream o;o<<x;return o.str();}
template<class T> void pv(T a,T b){for(T it=a;it!=b;++it)cerr<<*it<<" ";cerr<<endl;}
const int INF = 1000000000;
const double EPS = 1e-10;

string decode(string s, int alpha, int beta) {
	for(string::iterator it = s.begin(); it != s.end(); ++it) {
		if(isalpha(*it)) *it = (alpha * (*it - 'a') + beta) % 26 + 'a';
	}
	return s;
}

int main() {
	int N;
	cin >> N;
	cin.ignore();
	while(N--) {
		string line;
		getline(cin, line);
		string ans = "";
		for(int i = 0; i < 26; i++) {
			for(int j = 0; j < 26; j++) {
				string s = decode(line, i, j);
				if(s.find("that") != string::npos || s.find("this") != string::npos) {
					ans = s;
				}
			}
		}
		cout << ans << endl;
	}
}