#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
// using mint = modint1000000007;
#endif
#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;

inline void scan(int &a) { cin >> a; }
inline void scan(unsigned int &a) { cin >> a; }
inline void scan(long long &a) { cin >> a; }
inline void scan(unsigned long long &a) { cin >> a; }
inline void scan(float &a) { cin >> a; }
inline void scan(double &a) { cin >> a; }
inline void scan(long double &a) { cin >> a; }
inline void scan(char &a) { cin >> a; }
inline void scan(string &a) { cin >> a; }
inline void scan(vector<bool> &vec) { for (int i = 0; i < int(vec.size()); i++) { int a; scan(a); vec[i] = a; } }

template<typename T> inline void scan(vector<T> &vec);
template<typename T, size_t size> inline void scan(array<T, size> &vec);
template<typename T> inline void scan(deque<T> &deq);
template<typename T, typename U> inline void scan(pair<T, U> &p);

template<typename T> inline void scan(vector<T> &vec) { for (auto &i : vec) scan(i); }
template<typename T, size_t size> inline void scan(array<T, size> &vec) { for (auto &i : vec) scan(i); }
template<typename T> inline void scan(deque<T> &deq) { for (auto &i : deq) scan(i); }
template<typename T, typename U> inline void scan(pair<T, U> &p) { scan(p.first); scan(p.second); }
template<typename T> inline void scan(T &a) { cin >> a; }
inline void read() { }
template<typename T, typename... U> inline void read(T &a, U &...b) { scan(a); read(b...); }

inline void write(const int &a) { cout << a; }
inline void write(const unsigned int &a) { cout << a; }
inline void write(const long long &a) { cout << a; }
inline void write(const unsigned long long &a) { cout << a; }
inline void write(const float &a) { cout << a; }
inline void write(const double &a) { cout << a; }
inline void write(const long double &a) { cout << a; }
inline void write(const char &a) { cout << a; }
inline void write(const string &a) { cout << a; }

template<typename T> inline void write(const vector<T> &vec);
template<typename T, size_t size> inline void write(const array<T, size> &vec);
template<typename T> inline void write(const deque<T> &deq);
template<typename T, typename U> inline void write(const pair<T, U> &p);

template<typename T> inline void write(const vector<T> &vec) {
    for (int i = 0; i < int(vec.size()); i++) {
        if (i) write(' ');
        write(vec[i]);
    }
}

template<typename T, size_t size> inline void write(const array<T, size> &vec) {
    for (int i = 0; i < int(vec.size()); i++) {
        if (i) write(' ');
        write(vec[i]);
    }
}

template<typename T> inline void write(const deque<T> &deq) {
    for (int i = 0; i < int(deq.size()); i++) {
        if (i) write(' ');
        write(deq[i]);
    }
}

template<typename T, typename U> inline void write(const pair<T, U> &p) {
    write(p.first);
    write(' ');
    write(p.second);
}

template<typename T> inline void write(const T &a) { cout << a; }

inline void print() { cout << '\n'; }
template<typename T> inline void print(const T &a) { write(a); cout << '\n'; }
template<typename T, typename... U> inline void print(const T &a, const U &...b) {
    write(a);
    ((cout << ' ', write(b)), ...);
    write('\n');
}
template<typename T> inline void debug_impl(const char *name, const T &value) {
    cerr << name << " = ";
    write(value);
    cerr << '\n';
}

template<typename T, typename ... U> inline void debug_impl(const char *names, const T &value, const U &...values) {
    const char *comma = strchr(names, ',');
    cerr.write(names, comma - names);
    cerr << " = ";
    write(value);
    cerr << ", ";
    while (*++comma == ' ');
    debug_impl(comma, values...);
}

using ll = long long;
using ld = long double;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template<typename T> using pq = priority_queue<T>;
template<typename T> using pq_g = priority_queue<T, vector<T>, greater<T>>;

#define overload3(a, b, c, d, ...) d
#define overload4(a, b, c, d, e, ...) e
#define rep1(n) for (ll i = 0; i < (n); i++)
#define rep2(i, n) for (ll i = 0; i < (n); i++)
#define rep3(i, a, b) for (ll i = (a); i < (b); i++)
#define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(n) for (ll i = (n) - 1; i >= 0; i--)
#define rrep2(i, n) for (ll i = (n) - 1; i >= 0; i--)
#define rrep3(i, a, b) for (ll i = (b) - 1; i >= (a); i--)
#define rrep4(i, a, b, c) for (ll i = (a) + ((b) - (a) - 1) / (c) * (c); i >= (a); i -= (c))
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all1(v) (v).begin(), (v).end()
#define all2(v, n) (v).begin(), (v).begin() + (n)
#define all3(v, a, b) (v).begin() + (a), (v).begin() + (b)
#define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__)
#define rall(v) (v).rbegin(), (v).rend()
#define UNIQUE(v) (v).erase(unique((v).begin(), (v).end()), (v).end())
#define NP next_permutation
#define endl '\n'
#define INT(...) int __VA_ARGS__; read(__VA_ARGS__);
#define LL(...) long long __VA_ARGS__; read(__VA_ARGS__);
#define ULL(...) unsigned long long __VA_ARGS__; read(__VA_ARGS__);
#define STR(...) string __VA_ARGS__; read(__VA_ARGS__);
#define CHAR(...) char __VA_ARGS__; read(__VA_ARGS__);
#define LD(...) long double __VA_ARGS__; read(__VA_ARGS__);
#define VEC(type, name, size) vector<type> name(size); read(name);
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); read(name);
#ifdef LOCAL
#define debug(...) debug_impl(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) ((void)0)
#endif

inline void Yes(bool a = true) { cout << (a ? "Yes" : "No") << endl; }
inline void No(bool a = true) { cout << (a ? "No" : "Yes") << endl; }
inline void YES(bool a = true) { cout << (a ? "YES" : "NO") << endl; }
inline void NO(bool a = true) { cout << (a ? "NO" : "YES") << endl; }
inline void Takahashi(bool a = true) { cout << (a ? "Takahashi" : "Aoki") << endl; }
inline void Alice(bool a = true) { cout << (a ? "Alice" : "Bob") << endl; }
inline void Possible(bool a = true) { cout << (a ? "Possible" : "Impossible") << endl; }

constexpr int INF = 1001001001;
constexpr ll LINF = 4004004004004004004LL;
constexpr ld pi = 3.14159265358979323846;
constexpr ld eps = 1e-9;
constexpr int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
constexpr int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };

ll modPow(ll a, ll n, ll mod = LINF) { ll ret = 1; ll x = a % mod; while (n) { if (n & 1) ret = ret * x % mod; x = x * x % mod; n >>= 1; } return ret; }
int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(ll x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
int lowbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int lowbit(ll x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int popcount(int x) { return __builtin_popcount(x); }
ll popcount(ll x) { return __builtin_popcountll(x); }
ll isqrt(ll x) { ll n = sqrtl(x); while ((n + 1) * (n + 1) <= x) n++; while (n * n > x) n--; return n; }
template<typename T> T floor(T a, T b) { return a / b - (a % b && (a ^ b) < 0); }
template<typename T> T ceil(T a, T b) { return floor(a + b - 1, b); }
template<typename T> T bmod(T a, T b) { return a - b * floor(a, b); }
template<typename T> pair<T, T> divmod(T a, T b) { return { floor(a, b), a - b * floor(a, b) }; }
template<typename T> auto MIN(const vector<T> &a) { return *min_element(all(a)); }
template<typename T> auto MAX(const vector<T> &a) { return *max_element(all(a)); }
template<typename T> auto SUM(const vector<T> &a) { return accumulate(all(a), T(0)); }
template<typename T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; }
template<typename T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }

void cincout() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
}

#include <cstdint>
using namespace std;

namespace HashMapImpl {
using u32 = uint32_t;
using u64 = uint64_t;

template <typename Key, typename Data>
struct HashMapBase;

template <typename Key, typename Data>
struct itrB
    : iterator<bidirectional_iterator_tag, Data, ptrdiff_t, Data*, Data&> {
  using base =
      iterator<bidirectional_iterator_tag, Data, ptrdiff_t, Data*, Data&>;
  using ptr = typename base::pointer;
  using ref = typename base::reference;

  u32 i;
  HashMapBase<Key, Data>* p;

  explicit constexpr itrB() : i(0), p(nullptr) {}
  explicit constexpr itrB(u32 _i, HashMapBase<Key, Data>* _p) : i(_i), p(_p) {}
  explicit constexpr itrB(u32 _i, const HashMapBase<Key, Data>* _p)
      : i(_i), p(const_cast<HashMapBase<Key, Data>*>(_p)) {}
  friend void swap(itrB& l, itrB& r) { swap(l.i, r.i), swap(l.p, r.p); }
  friend bool operator==(const itrB& l, const itrB& r) { return l.i == r.i; }
  friend bool operator!=(const itrB& l, const itrB& r) { return l.i != r.i; }
  const ref operator*() const {
    return const_cast<const HashMapBase<Key, Data>*>(p)->data[i];
  }
  ref operator*() { return p->data[i]; }
  ptr operator->() const { return &(p->data[i]); }

  itrB& operator++() {
    assert(i != p->cap && "itr::operator++()");
    do {
      i++;
      if (i == p->cap) break;
      if (p->occupied_flag[i] && !p->deleted_flag[i]) break;
    } while (true);
    return (*this);
  }
  itrB operator++(int) {
    itrB it(*this);
    ++(*this);
    return it;
  }
  itrB& operator--() {
    do {
      i--;
      if (p->occupied_flag[i] && !p->deleted_flag[i]) break;
      assert(i != 0 && "itr::operator--()");
    } while (true);
    return (*this);
  }
  itrB operator--(int) {
    itrB it(*this);
    --(*this);
    return it;
  }
};

template <typename Key, typename Data>
struct HashMapBase {
  using u32 = uint32_t;
  using u64 = uint64_t;
  using iterator = itrB<Key, Data>;
  using itr = iterator;

 protected:
  template <typename K>
  inline u64 randomized(const K& key) const {
    return u64(key) ^ r;
  }

  template <typename K,
            enable_if_t<is_same<K, Key>::value, nullptr_t> = nullptr,
            enable_if_t<is_integral<K>::value, nullptr_t> = nullptr>
  inline u32 inner_hash(const K& key) const {
    return (randomized(key) * 11995408973635179863ULL) >> shift;
  }
  template <
      typename K, enable_if_t<is_same<K, Key>::value, nullptr_t> = nullptr,
      enable_if_t<is_integral<decltype(K::first)>::value, nullptr_t> = nullptr,
      enable_if_t<is_integral<decltype(K::second)>::value, nullptr_t> = nullptr>
  inline u32 inner_hash(const K& key) const {
    u64 a = randomized(key.first), b = randomized(key.second);
    a *= 11995408973635179863ULL;
    b *= 10150724397891781847ULL;
    return (a + b) >> shift;
  }
  template <typename K,
            enable_if_t<is_same<K, Key>::value, nullptr_t> = nullptr,
            enable_if_t<is_integral<typename K::value_type>::value, nullptr_t> =
                nullptr>
  inline u32 inner_hash(const K& key) const {
    static constexpr u64 mod = (1LL << 61) - 1;
    static constexpr u64 base = 950699498548472943ULL;
    u64 res = 0;
    for (auto& elem : key) {
      __uint128_t x = __uint128_t(res) * base + (randomized(elem) & mod);
      res = (x & mod) + (x >> 61);
    }
    __uint128_t x = __uint128_t(res) * base;
    res = (x & mod) + (x >> 61);
    if (res >= mod) res -= mod;
    return res >> (shift - 3);
  }

  template <typename D = Data,
            enable_if_t<is_same<D, Key>::value, nullptr_t> = nullptr>
  inline u32 hash(const D& dat) const {
    return inner_hash(dat);
  }
  template <
      typename D = Data,
      enable_if_t<is_same<decltype(D::first), Key>::value, nullptr_t> = nullptr>
  inline u32 hash(const D& dat) const {
    return inner_hash(dat.first);
  }

  template <typename D = Data,
            enable_if_t<is_same<D, Key>::value, nullptr_t> = nullptr>
  inline Key data_to_key(const D& dat) const {
    return dat;
  }
  template <
      typename D = Data,
      enable_if_t<is_same<decltype(D::first), Key>::value, nullptr_t> = nullptr>
  inline Key data_to_key(const D& dat) const {
    return dat.first;
  }

  void reallocate(u32 ncap) {
    vector<Data> ndata(ncap);
    vector<bool> nf(ncap);
    shift = 64 - __lg(ncap);
    for (u32 i = 0; i < cap; i++) {
      if (occupied_flag[i] && !deleted_flag[i]) {
        u32 h = hash(data[i]);
        while (nf[h]) h = (h + 1) & (ncap - 1);
        ndata[h] = move(data[i]);
        nf[h] = true;
      }
    }
    data.swap(ndata);
    occupied_flag.swap(nf);
    cap = ncap;
    occupied = s;
    deleted_flag.resize(cap);
    fill(std::begin(deleted_flag), std::end(deleted_flag), false);
  }

  inline bool extend_rate(u32 x) const { return x * 2 >= cap; }

  inline bool shrink_rate(u32 x) const {
    return HASHMAP_DEFAULT_SIZE < cap && x * 10 <= cap;
  }

  inline void extend() { reallocate(cap << 1); }

  inline void shrink() { reallocate(cap >> 1); }

 public:
  u32 cap, s, occupied;
  vector<Data> data;
  vector<bool> occupied_flag, deleted_flag;
  u32 shift;
  static u64 r;
  static constexpr uint32_t HASHMAP_DEFAULT_SIZE = 4;

  explicit HashMapBase()
      : cap(HASHMAP_DEFAULT_SIZE),
        s(0),
        occupied(0),
        data(cap),
        occupied_flag(cap),
        deleted_flag(cap),
        shift(64 - __lg(cap)) {}

  itr begin() const {
    u32 h = 0;
    while (h != cap) {
      if (occupied_flag[h] && !deleted_flag[h]) break;
      h++;
    }
    return itr(h, this);
  }
  itr end() const { return itr(this->cap, this); }

  friend itr begin(const HashMapBase& h) { return h.begin(); }
  friend itr end(const HashMapBase& h) { return h.end(); }

  itr find(const Key& key) const {
    u32 h = inner_hash(key);
    while (true) {
      if (occupied_flag[h] == false) return this->end();
      if (data_to_key(data[h]) == key) {
        if (deleted_flag[h] == true) return this->end();
        return itr(h, this);
      }
      h = (h + 1) & (cap - 1);
    }
  }

  bool contain(const Key& key) const { return find(key) != this->end(); }

  itr insert(const Data& d) {
    u32 h = hash(d);
    while (true) {
      if (occupied_flag[h] == false) {
        if (extend_rate(occupied + 1)) {
          extend();
          h = hash(d);
          continue;
        }
        data[h] = d;
        occupied_flag[h] = true;
        ++occupied, ++s;
        return itr(h, this);
      }
      if (data_to_key(data[h]) == data_to_key(d)) {
        if (deleted_flag[h] == true) {
          data[h] = d;
          deleted_flag[h] = false;
          ++s;
        }
        return itr(h, this);
      }
      h = (h + 1) & (cap - 1);
    }
  }

  // tips for speed up :
  // if return value is unnecessary, make argument_2 false.
  itr erase(itr it, bool get_next = true) {
    if (it == this->end()) return this->end();
    s--;
    if (!get_next) {
      this->deleted_flag[it.i] = true;
      if (shrink_rate(s)) shrink();
      return this->end();
    }
    itr nxt = it;
    nxt++;
    this->deleted_flag[it.i] = true;
    if (shrink_rate(s)) {
      Data d = data[nxt.i];
      shrink();
      it = find(data_to_key(d));
    }
    return nxt;
  }

  itr erase(const Key& key) { return erase(find(key)); }

  int count(const Key& key) { return find(key) == end() ? 0 : 1; }

  bool empty() const { return s == 0; }

  int size() const { return s; }

  void clear() {
    fill(std::begin(occupied_flag), std::end(occupied_flag), false);
    fill(std::begin(deleted_flag), std::end(deleted_flag), false);
    s = occupied = 0;
  }

  void reserve(int n) {
    if (n <= 0) return;
    n = 1 << min(23, __lg(n) + 2);
    if (cap < u32(n)) reallocate(n);
  }
};

template <typename Key, typename Data>
uint64_t HashMapBase<Key, Data>::r =
    chrono::duration_cast<chrono::nanoseconds>(
        chrono::high_resolution_clock::now().time_since_epoch())
        .count();

}  // namespace HashMapImpl

/**
 * @brief Hash Map(base)　(ハッシュマップ・基底クラス)
 */

 template <typename Key>
struct HashSet : HashMapImpl::HashMapBase<Key, Key> {
  using HashMapImpl::HashMapBase<Key, Key>::HashMapBase;
};

int dp[101][100001];

void solve() {
    INT(N, M);
    VEC(int, U, N);
    VEC(int, V, M);
    const int X = SUM(V) + 1;
    dp[0][0] = true;
    for (int i = 0; i < M; i++) for (int j = 0; j <= X; j++) {
        if (!dp[i][j]) continue;
        dp[i + 1][j] = true;
        dp[i + 1][j + V[i]] = true;
    }

    HashSet<int> s;
    for (int j = 0; j <= X; j++) {
        if (dp[M][j]) {
            for (int i = 0; i < N; i++) s.insert(U[i] + j);
        }
    }
    print(s.size());
}

int main() {
    cincout();
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}