#include <bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...) void(0)
#endif

template <class T> std::istream& operator>>(std::istream& is, std::vector<T>& v) {
    for (auto& e : v) {
        is >> e;
    }
    return is;
}

template <class T> std::ostream& operator<<(std::ostream& os, const std::vector<T>& v) {
    for (std::string_view sep = ""; const auto& e : v) {
        os << std::exchange(sep, " ") << e;
    }
    return os;
}

template <class T, class U = T> bool chmin(T& x, U&& y) {
    return y < x and (x = std::forward<U>(y), true);
}

template <class T, class U = T> bool chmax(T& x, U&& y) {
    return x < y and (x = std::forward<U>(y), true);
}

template <class T> void mkuni(std::vector<T>& v) {
    std::ranges::sort(v);
    auto result = std::ranges::unique(v);
    v.erase(result.begin(), result.end());
}

template <class T> int lwb(const std::vector<T>& v, const T& x) {
    return std::distance(v.begin(), std::ranges::lower_bound(v, x));
}

using ll = long long;

using namespace std;

constexpr int INF = 1e9;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
    int N, Q;
    cin >> N >> Q;
    vector<int> A(N);
    cin >> A;

    vector<int> dp(N, INF), ndp(N, INF);
    dp[0] = 0;
    for (; Q--;) {
        int B;
        cin >> B;
        int mini = INF;
        debug(dp);
        for (int i = 0; i < N; i++) {
            if (dp[i] < INF) chmin(mini, dp[i] - i);
            if (A[i] == B) chmin(ndp[i], mini + i);
        }
        mini = INF;
        for (int i = N - 1; i >= 0; i--) {
            if (dp[i] < INF) chmin(mini, dp[i] + i);
            if (A[i] == B) chmin(ndp[i], mini - i);
            dp[i] = INF;
        }
        swap(dp, ndp);
        debug(dp);
    }

    int ans = ranges::min(dp);
    cout << ans << '\n';
    return 0;
}