#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
int n, m;
vector<int> me, a, nme;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  int num;
  for (int i = 1; i <= n; i++) {
    cin >> num;
    me.push_back(num);
  }
  for (int i = 1; i <= m; i++) {
    cin >> num;
    a.push_back(num);
  }
  for (int i = 0; i < 30; i++) {
    for (int j = 0; j < me.size(); j++) {
      if (me[j] & (1 << i)) {
        nme.push_back((1 << i));
      }
    }
  }
  sort(a.begin(), a.end());
  int ans = 0;
  int cm = 0;
  for (int i = 0; i < nme.size(); i++) {
    while (cm < a.size() and nme[i] >= (1 << a[cm])) {
      nme[i] -= (1 << a[cm]);
      cm += 1;
      ans += 1;
    }
  }
  cout << ans;
  return 0;
}
