Problem:
Score : 300 points

Problem Statement

E869120 found a chest which is likely to contain treasure.

However, the chest is locked. In order to open it, he needs to enter a string S consisting of lowercase English letters.

He also found a string S', which turns out to be the string S with some of its letters (possibly all or none) replaced with ?.

One more thing he found is a sheet of paper with the following facts written on it:

Condition 1: The string S contains a string T as a contiguous substring.

Condition 2: S is the lexicographically smallest string among the ones that satisfy Condition 1.

Print the string S.

If such a string does not exist, print UNRESTORABLE.

Constraints

1 \leq |S'|, |T| \leq 50

S' consists of lowercase English letters and ?.

T consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S
T'

Output

Print the string S.

If such a string does not exist, print UNRESTORABLE instead.

Sample Input 1

?tc????
coder

Sample Output 1

atcoder

There are 26 strings that satisfy Condition 1: atcoder, btcoder, ctcoder,..., ztcoder.
Among them, the lexicographically smallest is atcoder, so we can say S = atcoder.

Sample Input 2

??p??d??
abc

Sample Output 2

UNRESTORABLE

There is no string that satisfies Condition 1, so the string S does not exist.

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class AtCoderA
{
    static void Main()
    {
        var sc = new Scanner();

        string s = sc.Next();
        string t = sc.Next();

        if (s.Length < t.Length)
        {
            Console.WriteLine("UNRESTORABLE");
            return;
        }

        List<string> answers = new List<string>();
        for (int i = 0; i < s.Length - t.Length + 1; i++)
        {
            bool ok = true;
            string tmpAnswer = "";
            for (int j = 0; j < i; j++)
            {
                tmpAnswer += s[j] == '?' ? "a" : s[j].ToString();
            }
            for (int j = 0; j < t.Length; j++)
            {
                if (s[i + j] != '?' && s[i + j] != t[j])
                {
                    ok = false;
                    break;
                }
                else
                {
                    tmpAnswer += t[j];
                }
            }
            for (int j = 0; j < s.Length - i - t.Length; j++)
            {
                tmpAnswer += s[i + t.Length + j] == '?' ? "a" : s[i + t.Length + j].ToString();
            }
            if (ok)
            {
                answers.Add(tmpAnswer);
            }

        }

        if (answers.Count > 0)
        {
            string answer = answers.OrderBy(str => str).First();
            Console.WriteLine(answer);
        }
        else
        {
            Console.WriteLine("UNRESTORABLE");
            return;
        }
    }

    class Scanner
    {
        private string[] _line;
        private int _index;
        private const char Separator = ' ';

        public Scanner()
        {
            _line = new string[0];
            _index = 0;
        }

        public string Next()
        {
            while (_index >= _line.Length)
            {
                _line = Console.ReadLine().Split(Separator);
                _index = 0;
            }

            return _line[_index++];
        }

        public int NextInt() => int.Parse(Next());
        public long NextLong() => long.Parse(Next());
        public double NextDouble() => double.Parse(Next());
        public decimal NextDecimal() => decimal.Parse(Next());
        public char NextChar() => Next()[0];
        public char[] NextCharArray() => Next().ToCharArray();

        public string[] Array()
        {
            _line = Console.ReadLine().Split(Separator);
            _index = _line.Length;
            return _line;
        }

        public int[] IntArray() => Array().Select(int.Parse).ToArray();
        public long[] LongArray() => Array().Select(long.Parse).ToArray();
        public double[] DoubleArray() => Array().Select(double.Parse).ToArray();
        public decimal[] DecimalArray() => Array().Select(decimal.Parse).ToArray();
    }
}