fun main(args: Array<String>) {
    val s = readLine()?: return
    val t = readLine()?: return

    for (i in (s.lastIndex - t.lastIndex) downTo 0) {
        var match = true
        for (j in t.indices) {
            if (s[i + j] == '?' || s[i + j] == t[j]) {
                continue
            }
            match = false
            break
        }
        if (match) {
            val result = s.replaceRange(i, i + t.length, t).replace('?', 'a')
            println(result)
            return
        }
    }
    println("UNRESTORABLE")
}