#include<bits/stdc++.h> using namespace std; #define ll long long #define fi first #define se second const bool Multitest = 0; const int N = 1e5 + 10; pair<int, int> a[N]; int b[N]; int n, m; void maximize(int& a, int b) { if(a < b) a = b; } namespace sub1 { const int Nsub = 1e3 + 10; int dp[Nsub][Nsub]; void solve() { sort(a + 1, a + 1 + n); sort(b + 1, b + 1 + m); for(int i = 1 ; i <= m ; i++) { for(int j = 1 ; j <= n ; j++) { dp[i][j] = dp[i - 1][j - 1] + (a[j].se <= b[i]); maximize(dp[i][j], dp[i][j - 1]); } } cout << dp[m][n]; } } void work() { cin >> n >> m; for(int i = 1 ; i <= n ; i++) { cin >> a[i].se >> a[i].fi; } for(int i = 1 ; i <= m ; i++) cin >> b[i]; if(n <= 1000 && m <= 1000) sub1::solve(); } int main() { ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); int q = 1; if(Multitest) cin >> q; while(q--) work(); }