fun main() {
    val builder = StringBuilder()

    val n = readInputLine().toLong()

    builder.appendln(gcd(n, n * (n + 1L) / 2L))

    print(builder.toString())
}

fun readInputLine(): String {
    return readLine()!!
}

tailrec fun gcd(a: Long, b: Long): Long =
    when {
        b > a -> gcd(b, a)
        b == 0L -> a
        else -> gcd(b, a % b)
    }