#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#define ll long long
#define pb push_back
#define endl '\n'
#define pii pair<ll,ll>
#define F first
#define S second
#define double long double
#define all(x) (x).begin(),(x).end()
using namespace std;
using namespace __gnu_pbds;
typedef tree<ll , null_type , less_equal<ll> ,rb_tree_tag ,tree_order_statistics_node_update >ordered_set;
const int MOD = 1e9 + 7;
const int N=1e6 + 7 ;
const ll INF= 1e18+10;
struct trp{ll F,S,T;};
ll po1(ll x,ll y)
{
ll ans = 1;
while(y){
if( y & 1 ) ans *=x;
y /= 2;
x *=x;
x %= MOD;
ans %= MOD;
}
return ans;
}
ll b[N];
ll n , m;
pii a[N];
bool cmp(pii a,pii b)
{
if(a.S !=b.S) return a.S < b.S;
return a.F < b.F;
}
void solve()
{
cin >> n >> m;
for(ll i= 1; i <= n ; i ++ ) cin>> a[i].F >> a[i].S;
for(ll i= 1;i <= m ; i ++ ) cin >> b[i];
sort(a + 1 , a + n + 1, cmp);
sort(b + 1 , b + m + 1);
ll l = n , r = m;
while(r > 0 && l > 0){
if(a[l].F <= b[r]){
r --;
l --;
}
else l --;
}
cout << m - r << endl;
}
int main(){
//ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//freopen(".in" , "r" , stdin);freopen(".out" , "w" , stdout);
int t = 1;
//cin >> t;
while(t--) {solve() ; }
}
