fun main(args: Array<String>){
    var s = readLine()!!
    val t = readLine()!!
    if(t.length > s.length){
        println("UNRESTORABLE")
        return
    }

    for(i in s.length - t.length downTo 0){
        var f = true
        var si = i
        for(j in 0 until t.length){
            f = f && (s[si] == '?' || s[si] == t[j])
            si++
        }
        if(f){
            s = s.replaceRange(i, i+t.length, t)
            s = s.replace('?', 'a')
            println(s)
            return
        }
    }
    println("UNRESTORABLE")
}