#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;

int main()
{   string s,t;
    int n;

    cin>>n;


    while(n--){

        s.clear();
        t.clear();

        cin>>s>>t;

        for(int i=0;i<max(s.size(),t.size());i++){
            if(isalpha(s[i]))cout<<s[i];
            if(isalpha(t[i]))cout<<t[i];
        }
        cout<<"\n";
    }

    return 0;
}