using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;

namespace AtCorder
{
    class Program
    {
        static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(Console.In, ' '));
        }


        public void Solve(ConsoleInput cin)
        {
            var S = cin.Read;
            var _T = cin.Read;
            var T = _T.ToCharArray();
            var index = -1;
            for(int i = S.Length - T.Length; i >= 0 ; i--)
            {
                var sub = S.Substring(i, T.Length).ToCharArray();
                var flag = true;
                for(int j = 0; j < T.Length; j++)
                {
                    if(sub[j] != '?' && sub[j] != T[j])
                    {
                        flag = false;
                        break;
                    }
                }
                if (flag)
                {
                    index = i;
                    break;
                }
            }
            if(index == -1)
            {
                WriteLine("UNRESTORABLE");
                return;
            }

            var ans = new char[S.Length];
            var s = S.ToCharArray();
            for(int i = 0; i < S.Length; i++)
            {
                if(i != index)
                {
                    if (s[i] != '?')
                    {
                        ans[i] = s[i];
                    }
                    else
                    {
                        ans[i] = 'a';
                    }
                }
                else
                {
                    for(int j = 0; j < T.Length; j++)
                    {
                        ans[i + j] = T[j];
                    }
                    i += T.Length - 1;
                }
            }
            WriteLine(ans);
        }

        public class ConsoleInput
        {
            private readonly System.IO.TextReader _stream;
            private char _separator = ' ';
            private Queue<string> inputStream;
            public ConsoleInput(System.IO.TextReader stream, char separator = ' ')
            {
                this._separator = separator;
                this._stream = stream;
                inputStream = new Queue<string>();
            }
            public string Read
            {
                get
                {
                    if (inputStream.Count != 0) return inputStream.Dequeue();
                    string[] tmp = _stream.ReadLine().Split(_separator);
                    for (int i = 0; i < tmp.Length; ++i)
                        inputStream.Enqueue(tmp[i]);
                    return inputStream.Dequeue();
                }
            }
            public string ReadLine { get { return _stream.ReadLine(); } }
            public int ReadInt { get { return int.Parse(Read); } }
            public long ReadLong { get { return long.Parse(Read); } }
            public double ReadDouble { get { return double.Parse(Read); } }
            public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret; }
            public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
            public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
        }
    }
}

Measured memory_bytes: 11348