#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll N = 1e5 + 2;
pair < ll, ll > P[N];
int main() {
ll n, m, r, lo, mid, hi, x, y, i, j, s, mn, ans, t, mx, can = 0;
cin >> n >> m;
for (i = 1; i <= n; i ++) {
cin >> P[i].second >> P[i].first;
}
ll b[m + 2], a[n + 2];
for (i = 1; i <= m; i ++) {
cin >> b[i];
}
sort ( b + 1, b + m + 1);
sort ( P + 1, P + n + 1);
for (i = 1; i <= n; i ++) a[i] = P[i].second;
vector < ll > v;
j = n;
for (i = m; i >= 1; i --) {
while ( j >= 1 && a[j] > b[i]) j --;
if ( j== 0) break;
j --;
}
cout<< m - i<< endl;
}
