// UUID: 60450dd8-3471-4fbd-9ec5-5a2b13e5aec9
#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const int MAXN = 2001;
const ll INF = 1e15;
const ll MOD = 1e9+7;

ll a[MAXN], b[MAXN], dp[MAXN][MAXN];
map<ll, int> value_to_bidx;

void solve() {
    int n, m; cin >> n >> m;
    a[0] = INF;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= m; i++) cin >> b[i];
    for (int i = 1; i <= m; i++) {
        value_to_bidx[b[i]] = i;
    }

    vector<int> st;
    st.emplace_back(0);
    dp[0][0] = 1;
    for (int i = 1; i <= n; i++) {

        while (!st.empty() && a[st.back()] <= a[i]) st.pop_back();
        st.emplace_back(i);

        for (int j = st.size()-1; j >= 1; j--) {
            if (value_to_bidx.count(a[st[j]])) {
                int idx = value_to_bidx[a[st[j]]];

                int l = st[j-1]+1, r = st[j];
                for (int k = l; k <= r; k++) {
                    dp[i][idx] += dp[k-1][idx-1];
                    dp[i][idx] %= MOD;
                }
            }
        }
    }
    cout << dp[n][m] << "\n";
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int t = 1; 
    // cin >> t;
    while (t--) solve();
    return 0;
}