#include <bits/stdc++.h>
using namespace std;
template <class F, class T>
T convert(F a, int p = -1) {
  stringstream ss;
  if (p >= 0) ss << fixed << setprecision(p);
  ss << a;
  T r;
  ss >> r;
  return r;
}
template <class T>
T gcd(T a, T b) {
  T r;
  while (b != 0) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
template <class T>
T sqr(T x) {
  return x * x;
}
template <class T>
T cube(T x) {
  return x * x * x;
}
template <class T>
int getbit(T s, int i) {
  return (s >> i) & 1;
}
template <class T>
T onbit(T s, int i) {
  return s | (T(1) << i);
}
template <class T>
T offbit(T s, int i) {
  return s & (~(T(1) << i));
}
template <class T>
int cntbit(T s) {
  return s == 0 ? 0 : cntbit(s >> 1) + (s & 1);
}
const int bfsz = 1 << 16;
char bf[bfsz + 5];
int rsz = 0;
int ptr = 0;
char gc() {
  if (rsz <= 0) {
    ptr = 0;
    rsz = (int)fread(bf, 1, bfsz, stdin);
    if (rsz <= 0) return EOF;
  }
  --rsz;
  return bf[ptr++];
}
void ga(char &c) {
  c = EOF;
  while (!isalpha(c)) c = gc();
}
int gs(char s[]) {
  int l = 0;
  char c = gc();
  while (isspace(c)) c = gc();
  while (c != EOF && !isspace(c)) {
    s[l++] = c;
    c = gc();
  }
  s[l] = '\0';
  return l;
}
template <class T>
bool gi(T &v) {
  v = 0;
  char c = gc();
  while (c != EOF && c != '-' && !isdigit(c)) c = gc();
  if (c == EOF) return false;
  bool neg = c == '-';
  if (neg) c = gc();
  while (isdigit(c)) {
    v = v * 10 + c - '0';
    c = gc();
  }
  if (neg) v = -v;
  return true;
}
const double PI = acos(-1.0);
const double eps = 1e-9;
const int inf = (int)1e9 + 5;
const long long linf = (long long)1e17 + 5;
const long long mod = 10003;
long long n1[33], n2[33];
int a;
int n, m;
int main() {
  gi(n);
  gi(m);
  memset(n1, 0, sizeof(n1));
  memset(n2, 0, sizeof(n2));
  for (int i = 0; i < (n); ++i) {
    gi(a);
    for (int j = 0; j < (31); ++j)
      if (getbit(a, j)) n1[j]++;
  }
  for (int i = 0; i < (m); ++i) {
    gi(a);
    n2[a]++;
  }
  long long res = 0;
  bool flag = true;
  for (int i = 0; i < (31); ++i) {
    if (!flag) break;
    while (n2[i] > 0) {
      while (n1[i] > 0 && n2[i] > 0) {
        n1[i]--;
        n2[i]--;
        res++;
      }
      if (n2[i] > 0) {
        flag = false;
        for (int j = i + 1; j <= 30; j++) {
          if (n1[j] > 0) {
            flag = true;
            n1[j]--;
            for (int k = (i); k <= (j - 1); ++k) n1[k]++;
            n1[i]++;
            break;
          }
        }
      }
      if (!flag) break;
    }
  }
  cout << res;
  return 0;
}
