#include <bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
*/
using namespace std;
// using namespace __gnu_pbds;
using namespace chrono;
// mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
/*
template <class T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
*/
//***************** CONSTANTS *****************
//***************** GLOBAL VARIABLES *****************
//***************** AUXILIARY STRUCTS *****************
//***************** MAIN BODY *****************
void solve(){
int N, M;
cin >> N >> M;
array<int, 2> A[N];
for(auto& [v, s] : A)
cin >> s >> v;
int B[M];
for(int &s : B) cin >> s;
sort(A, A + N);
sort(B, B + M);
int lo = 0, hi = M, ans = 0;
while(lo <= hi){
int mid = (lo + hi) >> 1;
int j = 0;
for(int i = 0; i < N && j < mid; i++){
auto [v, s] = A[i];
j += (s <= B[M - mid + j]);
}
if(j == mid){
lo = mid + 1;
ans = mid;
}
else hi = mid - 1;
}
cout << ans << '\n';
}
//***************** *****************
int32_t main(){
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
#ifdef LOCAL
auto begin = high_resolution_clock::now();
#endif
int tc = 1;
// cin >> tc;
for (int t = 0; t < tc; t++)
solve();
#ifdef LOCAL
auto end = high_resolution_clock::now();
cout << fixed << setprecision(4);
cout << "Execution Time: " << duration_cast<duration<double>>(end - begin).count() << "seconds" << endl;
#endif
return 0;
}
/*
If code gives a WA, check for the following :
1. I/O format
2. Are you clearing all global variables in between tests if multitests are a thing
3. Can you definitively prove the logic
4. If the code gives an inexplicable TLE, and you are sure you have the best possible complexity,
use faster io
*/
