fun main() {
    var n = readLine()!!.toLong().toString(2).toCharArray()
    var found = false
    for (i in n.indices) {
        if (n[i] == '0') continue
        if (!found) {
            found = true
        } else {
            n[i] = '0'
        }
    }
    println(n.concatToString().toLong(2))
}