import kotlin.math.min

fun main() {
    val builder = StringBuilder()

    // 解説読んだ
    val n = readInputLine().toInt()

    val ys = readInputLine().split(" ").map { it.toLong() }.toLongArray()
    ys.sort()

    when(n) {
        2 -> builder.appendln(ys[1] - ys[0])
        3 -> builder.appendln(ys[2] - ys[0])
        else -> {
            val dp = LongArray(n)
            dp[0] = 1_000_000_000_000L
            dp[1] = ys[1] - ys[0]
            dp[2] = ys[2] - ys[0]
            for (i in 3 until n) {
                dp[i] = min(dp[i - 2] + ys[i] - ys[i - 1], dp[i - 3] + ys[i] - ys[i - 2])
            }
            builder.appendln(dp[n - 1])
        }
    }

    print(builder.toString())
}

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