#include <bits/stdc++.h> using namespace std; using ll = long long; const int N = 1e5+5; int n, m; ll frm[N]; vector<pair<ll,ll>> pic; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cin >> n >> m; for( int i=0;i<n;i++ ) { ll a, b; cin >> a >> b; pic.push_back( {-b, -a} ); } for( int i=0;i<m;i++ ) { ll a; cin >> a; frm[i] = -a; } sort( pic.begin(), pic.end() ); sort( frm, frm+m ); int ans = 0; for( int i=0;i<n;i++ ) { if( ans >= m ) break; if( frm[ans] <= pic[i].second ) ans++; } cout << ans << "\n"; return 0; }