#include <bits/stdc++.h>
#define FOR(i,x,n) for(int i=x; i<n; i++)
#define F0R(i,n) FOR(i,0,n)
#define ROF(i,x,n) for(int i=n-1; i>=x; i--)
#define R0F(i,n) ROF(i,0,n)
#define WTF cout << "WTF" << endl
#define IOS ios::sync_with_stdio(false); cin.tie(0)
#define F first
#define S second
#define pb push_back
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend()
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<int> VI;
typedef vector<LL> VLL;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
const int N = 2e5 + 7;
const int ALPHA = 27;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
const int LOG = 22;
int n, m;
int ms[N];
PII ns[N];
inline bool check(int x) {
if (x >= m) return 1;
int ptr = x;
F0R(i, n) if (ptr < m && ns[i].F <= ms[ptr]) ptr++;
return (ptr >= m);
}
int main() {
IOS;
cin >> n >> m;
F0R(i, n) cin >> ns[i].F >> ns[i].S;
F0R(i, m) cin >> ms[i];
sort(ns, ns + n, [](const PII a, const PII b) {return a.S < b.S;});
sort(ms, ms + m);
int l = 0, r = max(n, m) + 1;
while(l < r) {
int mid = (l + r) >> 1;
if(!check(mid)) l = mid + 1;
else r = mid;
}
cout << m - l;
}
