fun main(arr:Array<String>) {
    val src = readLine()!!
    val hint = readLine()!!
    var mtIndex = -1
    for(i in (0..src.length - hint.length)) {
        var mt = true
        for(j in hint.indices) {
            if(src[j+i] == '?') {
                continue
            }
            if(src[j+i] != hint[j]) {
                mt = false
                break
            }
        }
        if(mt) {
            mtIndex = i
        }
    }
    val ans = src.toMutableList()
    if(mtIndex >= 0) {
        for(i in hint.indices) {
            ans[i+mtIndex] = hint[i]
        }
        for(i in ans.indices) {
            if(ans[i] == '?') {
                ans[i] = 'a'
            }
        }
        println(ans.joinToString(""))
    } else {
        println("UNRESTORABLE")
    }

}
