#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 29;
int n, m;
int main(void) {
  while (cin >> n >> m && n && m) {
    priority_queue<long long, vector<long long>, greater<long long> > que;
    for (int i = 0; i < n; i++) {
      long long a;
      que.push((cin >> a, a));
    }
    for (int i = 0; i < m; i++) {
      long long b;
      cin >> b;
      if (!que.empty() && que.top() <= b) que.pop();
    }
    cout << que.size() << endl;
  }
  return 0;
}
