
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <cassert>
#include <iostream>
#include <cctype>
#include <sstream>
#include <string>
#include <list>
#include <vector>
#include <queue>
#include <set>
#include <stack>
#include <map>
#include <utility>
#include <numeric>
#include <algorithm>
#include <bitset>
#include <complex>
#include <fstream>
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vint;
typedef pair<int, int> pint;
#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
template<class T> T RoundOff(T a){ return int(a+.5-(a<0)); }
template<class T, class C> void chmax(T& a, C b){ if(a < b) a = b; }
template<class T, class C> void chmin(T& a, C b){ if(b < a) a = b; }
template<class T, class C> pair<T, C> mp(T a, C b){ return make_pair(a, b); }


int f(int y, int a, int b)
{	return (a * y + b) % 26;	}

int main()
{
	int n;
	cin >> n;

	rep(i, n)
	{
		string str;
		cin.sync();
		getline(cin, str);
		int len = str.size();

		for(int a = 0; ; a++)
		{
			if(a % 2 != 0 && a % 13 != 0)
			{
				rep(b, 26)
				{
					// Ï·Îe[u
					int v[26];
					rep(y, 26)
						v[f(y, a, b)] = y;
					

					// Ï·
					string con = str;
					rep(in, len)
						if('a' <= con[in] && con[in] <= 'z')
							con[in] = v[con[in] - 'a'] + 'a';

					// Î`FbN
					rep(in, len - 3)
					{
						if(con.substr(in, 4) == "that" || con.substr(in, 4) == "this")
						{
							cout << con << endl;
							goto ng;
						}
					}
				}
			}
		}
ng:
		;
	}
	return 0;
}