local S, T = io.read("l","l")
local function match(i)
    local ss = S:sub(i, i+#T-1)
    for k=1,#T do
        local c = ss:sub(k,k)
        local d = T:sub(k,k)
        if c == '?' then
        elseif c == d then
        else
            return false
        end
    end
    return true
end
for i=#S-#T+1,1,-1 do
    if match(i) then
        local t = {}
        for k=1,i-1 do
            local c = S:sub(k,k)
            if c == '?' then
                table.insert(t, 'a')
            else
                table.insert(t, c)
            end
        end
        for k=i,i+#T-1 do
            table.insert(t, T:sub(k-i+1,k-i+1))
        end
        for k=i+#T,#S do
            local c = S:sub(k,k)
            if c == '?' then
                table.insert(t, 'a')
            else
                table.insert(t, c)
            end
        end
        print(table.concat(t, ""))
        return
    end
end
print("UNRESTORABLE")