#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;

class cipher{
public:
    char letter;
    int frequency;
};
bool comp(const cipher &A,const cipher &B){
    if(A.frequency<B.frequency)
        return true;
    else
        return false;
}
vector<cipher> cipherF;
int posOf(char c)
{
    int i;
    for(i=0;i<26;++i)
        if(cipherF[i].letter == c)
            return i;
    return -1;


}
int main()
{

    int t;
    cin>>t;
    string tmp;
    getline(cin,tmp);
    while(t--){
        cipherF.clear();
        for(int i=97;i<=122;++i)
        {
            cipher cip;
            cip.letter = i;
            cip.frequency = 0;
            cipherF.push_back(cip);

        }
        string txtF,cipherText;
        getline(cin,txtF);
        getline(cin,cipherText);

        for(int i=0;i<cipherText.size();++i)
        {
            char c = tolower(cipherText[i]);
            ++(cipherF[c-97].frequency);
        }

        stable_sort(cipherF.begin(),cipherF.end(),comp);
        for(int i=0;i<cipherText.size();++i)
        {
            int pos = posOf(cipherText[i]);
            if(pos == -1)
                continue;
            else if(isupper(cipherText[i]))
                cipherText[i] = toupper(txtF[pos]);
            else
                cipherText[i] = txtF[pos];


        }
        cout<<cipherText<<endl;



    }
}