#include <bits/stdc++.h>
using namespace std;
void Yes() {
  cout << "Yes" << endl;
  exit(0);
}
void No() {
  cout << "No" << endl;
  exit(0);
}
const int MAX_SIZE = 1000010;
class mint {
 public:
  static long long MOD;
  long long x;
  mint() : x(0) {}
  mint(long long x) : x(x % MOD) {}
  mint operator-() const { return x ? MOD - x : 0; }
  mint &operator+=(const mint &a) {
    if ((x += a.x) >= MOD) {
      x -= MOD;
    }
    return *this;
  }
  mint &operator-=(const mint &a) { return *this += -a; }
  mint &operator*=(const mint &a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint &operator/=(const mint &a) { return (*this *= power(MOD - 2)); }
  mint operator+(const mint &a) const { return mint(*this) += a; }
  mint operator-(const mint &a) const { return mint(*this) -= a; }
  mint operator*(const mint &a) const { return mint(*this) *= a; }
  mint operator/(const mint &a) const { return mint(*this) /= a; }
  bool operator<(const mint &a) const { return x < a.x; }
  bool operator==(const mint &a) const { return x == a.x; }
  const mint power(long long N) {
    if (N == 0) {
      return 1;
    } else if (N % 2 == 1) {
      return *this * power(N - 1);
    } else {
      mint half = power(N / 2);
      return half * half;
    }
  }
};
long long mint::MOD = 1e9 + 7;
istream &operator>>(istream &stream, mint &a) { return stream >> a.x; }
ostream &operator<<(ostream &stream, const mint &a) { return stream << a.x; }
mint inv[MAX_SIZE];
mint fact[MAX_SIZE];
mint factinv[MAX_SIZE];
void init() {
  inv[1] = 1;
  for (int i = 2; i < MAX_SIZE; i++) {
    inv[i] = (-inv[mint::MOD % i]) * (mint::MOD / i);
  }
  fact[0] = factinv[0] = 1;
  for (int i = 1; i < MAX_SIZE; i++) {
    fact[i] = mint(i) * fact[i - 1];
    factinv[i] = inv[i] * factinv[i - 1];
  }
}
mint choose(int n, int k) {
  if (n >= 0 && k >= 0 && n - k >= 0) {
    return fact[n] * factinv[k] * factinv[n - k];
  }
  return 0;
}
long long gcd(long long x, long long y) { return y ? gcd(y, x % y) : x; }
int N, M;
int S[2010];
int T[2010];
vector<int> chars[100010];
mint dp[2010][2010];
bool visited[2010][2010];
mint calc(int x, int y) {
  if (visited[x][y]) {
    return dp[x][y];
  }
  dp[x][y] = calc(x - 1, y);
  for (auto e : chars[S[x - 1]]) {
    if (e < y) {
      dp[x][y] += calc(x - 1, e);
    }
  }
  visited[x][y] = true;
  return dp[x][y];
}
int main() {
  cin >> N >> M;
  for (auto i = 0; i < N; i++) {
    cin >> S[i];
  }
  for (auto i = 0; i < M; i++) {
    cin >> T[i];
  }
  for (auto i = 0; i < M; i++) {
    chars[T[i]].push_back(i);
  }
  fill(&visited[0][0], &visited[0][0] + 2010 * 2010, false);
  for (auto j = 0; j <= M; j++) {
    dp[0][j] = 1;
    visited[0][j] = true;
  }
  cout << calc(N, M) << endl;
}
