/**
 * TLE submission that uses an array of longs and bit operations to track which
 * locations are have been visited for each passenger.
 *
 * Time complexity O(n*n/63)
 */

fun main() {
    var numPassengers = readln().toInt()
    var steps = numPassengers * 2
    var locationSequence = IntArray(steps)
    var pickupIndex = IntArray(numPassengers) { -1 }
    var dropoffIndex = IntArray(numPassengers)
    var locationMax = 0
    for (index in 0..numPassengers * 2 - 1) {
        val (passenger, location) = readln().split(" ").map { it.toInt() }
        locationSequence[index] = location - 1
        if (pickupIndex[passenger - 1] == -1) {
            pickupIndex[passenger - 1] = index
        } else {
            dropoffIndex[passenger - 1] = index
        }
        if (location > locationMax) {
            locationMax = location
        }
    }
    var visitedSize = (locationMax)/63;
    if (visitedSize * 63 < 2*numPassengers) {
        visitedSize++
    }
    var complaints = 0L
    for (passengerIndex in 0..numPassengers - 1) {
        var locationsVisited = LongArray(visitedSize)
        for (index in pickupIndex[passengerIndex]..dropoffIndex[passengerIndex]) {
            var location = locationSequence[index]
            var locationsVisitedIndex = location / 63
            var locationBit = location % 63
            if ((locationsVisited[locationsVisitedIndex] and (1L shl locationBit)) == 0L) {
                locationsVisited[locationsVisitedIndex] = locationsVisited[locationsVisitedIndex] or (1L shl locationBit);
            } else {
                complaints += 1;
            }
        }
    }
    println(complaints)
}