fun main() {
    var n = readLine()!!.toLong()
    var s = StringBuilder()

    do {
        val mod = n % 26
        if (mod != 0L) {
            s.append('a' + ((mod).toInt()) - 1)
            n = (n - mod) / 26
        } else {
            s.append('z')
            n = (n - 26) / 26
        }
    } while (n != 0L)

    println(s.reverse())
}