import java.util.*

fun main(args: Array<String>){
    var S: String = readLine()!!
    var T: String = readLine()!!
    var found = false
    var count = 0

    for(i in (S.length -T.length) downTo 0){
        var OK = true
        for(j in 0 until T.length){
            if(S[i+j] != '?' && (T[j] != S[i+j])){
                OK = false
            }
        }

        if(OK){
            count = i
            found = true
            break
        }
    }

    if(found){
        for(i in 0 until S.length){
            if(i >= count && i < count+T.length){
                print(T[i-count])
            } else if(S[i] == '?'){
                print('a')
            } else {
                print(S[i])
            }
        }

    } else {
        System.out.println("UNRESTORABLE")
    }


}