import java.lang.StringBuilder

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

