// File exhibition.cpp created on 02.10.2025 at 11:14:16
#include <bits/stdc++.h>
using i64 = long long;
#ifdef DEBUG
#include "/home/ahmetalp/Desktop/Workplace/debug.h"
#else
#define debug(...) void(23)
#endif
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int N, M;
std::cin >> N >> M;
std::vector<std::array<int, 2>> A(N);
std::vector<int> B(M);
for (int i = 0; i < N; ++i) {
std::cin >> A[i][1] >> A[i][0];
}
for (int i = 0; i < M; ++i) {
std::cin >> B[i];
}
std::sort(A.begin(), A.end());
std::sort(B.begin(), B.end());
int p = M - 1;
for (int i = N - 1; i >= 0; --i) {
if (p == -1) {
break;
}
if (A[i][1] <= B[p]) {
p--;
}
}
std::cout << M - p - 1 << '\n';
return 0;
}
