fun createLIS(permutation: List<Int>): List<Int> {
    val minLast = IntArray(permutation.size + 1){permutation.size + 1}.also { it[0] = 0 }
    val prevValue = IntArray(permutation.size + 1)
    for (a in permutation) {
        val pos = minLast.lowerBound(a)
        prevValue[a] = minLast[pos - 1]
        minLast[pos] = a
    }
    val result = mutableListOf<Int>((minLast.last { it != permutation.size + 1 }))
    while (result.last() > 0) {
        result.add(prevValue[result.last()])
    }
    result.removeLast()
    return result.reversed()
}
inline fun IntArray.partitionPoint(predicate: (Int) -> Boolean): Int {
    var min = 0
    var max = size
    while (min < max) {
        val mid = (min + max) / 2
        if (predicate(this[mid])) {
            min = mid + 1
        }else {
            max = mid
        }
    }
    return max
}
fun IntArray.lowerBound(target: Int): Int {
    return partitionPoint { it < target }
}
fun main() {
    System.setProperty("kotlin.collections.convert_arg_to_set_in_removeAll", "true")
    val n = readLine()!!.trim().toInt()
    val permutation = readLine()!!.trim().split(' ').map(String::toInt)
    val forward = createLIS(permutation)
    val backward = createLIS(permutation.reversed().map { n - it + 1 }).reversed().map { n - it + 1 }
    val fix = forward.intersect(backward)
    println(fix.size)
    println(fix.toList().sorted().joinToString(" "))
}