#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define srtl(x)sort(all(x))
#define srtg(x)sort((x).begin(),(x).end(),greater<>())
#define rev(x) reverse(all(x))
#define lb(x,y) lower_bound(x.begin(),x.end(),y)-x.begin()
#define ub(x,y) upper_bound(x.begin(),x.end(),y)-x.begin()
#define ios ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define f first
#define s second
#define pb push_back
#define ins insert
#define next next_permutation
#define _b __builtin_popcount
#define ve vector
#define pii pair<int,int>
#define piii pair<int,pii>
#define vi vector<int>
#define vii vector<pii>
#define viii vector<piii>
#define vvi vector<vi>
//#define vs vector<string>
#define vb vector<bool>
#define pV(x)for(auto i:x)cout<<i<<" ";
#define geta(a){for(auto &i:a)cin>>i;}
#define fr(n)for(int i=0;i<n;i++)
#define Fr(n)for(int i=n-1;i>=0;i--)
#define suma(a)accumulate(a.begin(),a.end(),0LL)
#define br(x){cout<<x<<"\n";return;}
#define yesn cout<<"YES\n";
#define yes()br("YES");
#define no(){br("NO")}
#define alice() br("Alice");
#define bob() br("Bob");
#define cn continue;
#define cint const int
#define int long long
int mod=1000000007;
cint mod1=100000007;
cint mod2=998244353;
int ax[8]={0,1,0,-1,-1,1,1,-1};
int ay[8]={1,0,-1,0,1,-1,1,-1};
//bool on(int x,int y){return (x>=0&&x<n&&y>=0&&y<m);}
//int euc(int a,int b,int c,int d){return abs(a-c)+abs(b-d);}
int bp(int x,int y){
if(y==0)return 1;
int r=bp(x,y/2);
return (y&1)?r*r%mod*x%mod:r*r%mod;
}
int bpm(int x,int y){
if(y==0)return 1;
int r=bp(x,y/2);
return (y&1)?r*r*x:r*r;
}
int cinn(){
int n;
cin>>n;
return n;
}
#define w cinn()
int n,m;
void solve(){
cin>>n>>m;
int res=0;
vii v(n);
vi k(m);
for(int i=0;i<n;i++){
cin>>v[i].s>>v[i].f;
}
srtg(v);
for(int i=0;i<m;i++){
cin>>k[i];
}
srtg(k);
int pos=0;
for(int i=0;;i++){
while(i<n&&v[i].s>k[pos])i++;
if(pos==m||i==n)break;
pos++;
}
cout<<pos;
}
int32_t main(){
ios;
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
/*
5 4
19 5
10 20
5 1
3 5
3 4
18 5 4 2
2 2
5 10
6 20
7
8
3 4
10 20
5 1
3 5
4
6
10
4
3 2
1 2
1 2
1 2
1
1
4 2
28 1
8 8
6 10
16 9
4
3
8 8
508917604 35617051
501958939 840246141
485338402 32896484
957730250 357542366
904165504 137209882
684085683 775621730
552953629 20004459
125090903 607302990
433255278
979756183
28423637
856448848
276518245
314201319
666094038
149542543
4 3
3 6
7 10
3 10
6 15
3 6 3
*/
