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

    var lastIndex = -1
    outer@for (i in 0..s.length-t.length) {
        val ss = s.slice(i until i+t.length)
        for (j in t.indices) {
            if (ss[j] != t[j] && ss[j] != '?') continue@outer
        }
        // found
        lastIndex = i
    }

    if (lastIndex == -1) {
        println("UNRESTORABLE")
        return
    }

    val ans = s.toMutableList()
    for (i in ans.indices) {
        if (i >= lastIndex && i <= lastIndex+t.length-1) {
            ans[i] = t[i-lastIndex]
        } else if (ans[i] == '?') {
            ans[i] = 'a'
        }
    }

    println(ans.joinToString(""))
}