#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

ll op(ll a, ll b) {
    return min(a,b);
}

ll e() {
    return 2e18;
}

int main()
{
    int n, q;
    cin >> n >> q;
    int now = 0;
    vector<int> a(n);
    map<int, vector<int>> inv;
    rep(i,n) {
        cin >> a[i];
        --a[i];
        inv[a[i]].push_back(i);
    }
    vector<ll> dp(n, 2e18);
    dp[0] = 0;
    while(q--) {
        int b;
        cin >> b;
        --b;
        segtree<ll, op, e> segl(n), segr(n);
        rep(i,n) {
            segl.set(i, dp[i]-i);
            segr.set(i, dp[i]+i);
        }
        vector<ll> p(n, 2e18);
        swap(dp, p);
        for(int v : inv[b]) {
            ll val = min(segl.prod(0, v+1) + v, segr.prod(v, n)-v);
            dp[v] = val;
        }
    }
    cout << *min_element(dp.begin(),dp.end()) << endl;
    return 0;
}