import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Arrays;
import java.util.Comparator;
// User defined Pair class
class Pair {
int x;
int y;
// Constructor
public Pair(int x, int y) {
this.x = x;
this.y = y;
}
}
/*// class to define user defined comparator
class ArrayOfPairsSorter {
static void sort(Pair[] arr) {
Comparator<Pair> comparator = new Comparator<>() {
@Override
public int compare(Pair p1, Pair p2) {
if (p1.y - p2.y == 0) {
return p1.x - p2.x;
} else {
return p1.y - p2.y;
}
}
};
Arrays.sort(arr, comparator);
}
}
class MergeSort{
static void sort(Pair[] arr) {
while
}
static void breaker(Pair[] arr){
}
static void merge(Pair[] arr1, Pair[] arr2, Pair[] temp) {
while (arr1.length > 0 && arr2.length > 0) {
if (arr1[0].y < arr2[0].y){
temp
} else if (arr1[0].y > arr2[0].y) {
} else {
}
}
}
}*/
class SortTest {
public static void mergeSort(Pair[] elements) {
int n = elements.length;
Pair[] temp = new Pair[n];
mergeSortHelper(elements, 0, n - 1, temp);
}
private static void mergeSortHelper(Pair[] elements, int from, int to, Pair[] temp) {
if (from < to) {
int middle = (from + to) / 2;
mergeSortHelper(elements, from, middle, temp);
mergeSortHelper(elements, middle + 1, to, temp);
merge(elements, from, middle, to, temp);
}
}
private static void merge(Pair[] elements, int from,
int mid, int to, Pair[] temp) {
int i = from;
int j = mid + 1;
int k = from;
while (i <= mid && j <= to) {
if (elements[i].y < elements[j].y) {
temp[k] = elements[i];
i++;
} else if ( elements[i].y > elements[j].y){
temp[k] = elements[j];
j++;
} else {
if (elements[i].x < elements[j].x) {
temp[k] = elements[i];
i++;
} else {
temp[k] = elements[j];
j++;
}
}
k++;
}
while (i <= mid) {
temp[k] = elements[i];
i++;
k++;
}
while (j <= to) {
temp[k] = elements[j];
j++;
k++;
}
for (k = from; k <= to; k++) {
elements[k] = temp[k];
}
}
}
class joi2019_ho_t2 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int N = scanner.nextInt();
int M = scanner.nextInt();
Pair[] pictures = new Pair[N];
ArrayList<Integer> frame = new ArrayList<Integer>();
for (int i = 0; i < N; i++) {
pictures[i] = new Pair(scanner.nextInt(), scanner.nextInt());
}
for (int i = 0; i < M; i++) {
frame.add(scanner.nextInt());
}
//ArrayOfPairsSorter.sort(pictures);
SortTest.mergeSort(pictures);
Collections.sort(frame);
int frameCounter = M;
for (int i = N; i > 0; i--) {
if (frameCounter > 0) {
if (pictures[i - 1].x <= frame.get(frameCounter - 1)) {
frameCounter -= 1;
}
}
}
System.out.println(M - frameCounter);
}
}
