#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 1;


void solve(){
    int n, q; cin >> n >> q;
    vector<int> a(n), b(q);
    for(int i=0; i<n; i++) cin >> a[i];
    for(int j=0; j<q; j++) cin >> b[j];

    vector<vector<int>> dp(q+1, vector<int>(n, IINF));
    dp[0][0] = 0;
    for(int i=1; i<=q; i++){
        //左から走査
        int mn = IINF;
        for(int j=0; j<=n; j++){
            mn = min(mn, dp[i-1][j] - j);
            if(a[j] == b[i-1]){
                dp[i][j] = min(dp[i][j], j+mn);
            }
        }

        //右から走査
        mn = IINF;
        for(int j=n-1; j>=0; j--){
            mn = min(mn, dp[i-1][j] + j);
            if(a[j] == b[i-1]){
                dp[i][j] = min(dp[i][j], mn - j);
            }
        }
    }

    // for(int i=0; i<=q; i++){
    //     for(int j=0; j<n; j++){
    //         if(dp[i][j]==IINF) cout << -1 << ' ';
    //         else cout << dp[i][j] << ' ';
    //     }
    //     cout << '\n';
    // }

    int ans = IINF;
    for(int j=0; j<n; j++) ans = min(ans, dp[q][j]);

    cout << ans << '\n';
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int T=1;
    //cin >> T;
    while(T--) solve();
}