fun main(args: Array<String>) {
    val t = readLine()!!

    var pre = t[0]

    val ans = StringBuffer("")
    repeat(t.length) {
        if (t[it] == '?') {
            ans.append('D')
            pre = 'D'
        } else {
            ans.append(t[it])
            pre = t[it]
        }
    }
    println(ans)
}
