#include<bits/stdc++.h> using namespace std; typedef pair<int,int> pii; #define F first #define S second const int N = 1e5+87; pii a[N]; int n,m,c[N]; bool ok(int k) { int j = m-k; for (int i = 0; i < n && j < m; ++i) if (a[i].S <= c[j]) ++j; return j == m; } int main() { ios::sync_with_stdio(0); cin.tie(0); cin >> n >> m; for (int i = 0; i < n; ++i) cin >> a[i].S >> a[i].F; for (int i = 0; i < m; ++i) cin >> c[i]; sort(a,a+n); sort(c,c+m); int l=1,r=min(n,m); while (l<=r) { int k=(l+r)/2; if (ok(k)) l=k+1; else r=k-1; } cout << r << endl; }