fun main(args: Array<String>) {
    val s = readInputLine().toCharArray()
    val t = readInputLine().toCharArray()
    
    var ans = "UNRESTORABLE"
    
    for (i in s.size - t.size downTo 0) {
        var ok = true
        for (j in t.size - 1 downTo 0) {
            if (s[i + j] == '?') {
                continue
            }
            if (s[i + j] != t[j]) {
                ok = false
                break
            }
        }
        
        if (ok) {
            for (j in 0 until t.size) {
                s[i + j] = t[j]
            }
            ans = s.joinToString("").replace('?', 'a')
            break
        }
    }
    
    println(ans)
}

fun readInputLine(): String {
    return readLine()!!
}
