#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
int main()
{
    string s,t;
    cin>>s>>t;
    if (s.length()<t.length())cout<<"UNRESTORABLE";
    else
    {
        bool flag0=true;
        for (int i=s.length()-t.length(); i>=0; --i)
        {
            bool flag=true;
            for (int j=0; j<=t.length()-1; ++j)
                if (!(s[i+j]==t[j]||s[i+j]=='?'))
                {
                    flag=false;
                    break;
                }
            if (flag)
            {
                for (int j=0; j<=i-1; ++j)
                    if (s[j]=='?')
                        cout<<'a';
                    else cout<<s[j];
                cout<<t;
                for (int j=i+t.length(); j<=s.length()-1; ++j)
                    if (s[j]=='?')
                        cout<<'a';
                    else cout<<s[j];
                flag0=false;
                break;
            }
        }
        if (flag0)cout<<"UNRESTORABLE";
    }
}
