//#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <numeric>
#include <cmath>
#include <bit>
#include <cstdint>

#define rep(i,n) for(ll i = 0; i < n; i++) //[0,n)
#define srep(i,a,b) for(ll i = a; i < b; i++) //[a,b)
#define arep(i,a,b,d) for(ll i = a; i < b; i += d)
#define all(A) (A).begin(),(A).end()
#define rall(A) (A).rbegin(),(A).rend()
#define pmt(A) next_permutation(all(A))
using namespace std;
using ll = long long;
using ull = unsigned long long;
using pq = priority_queue<ll,vector<ll>,greater<ll>>;
const ll inf = 1LL<<60;
const int iinf = (int)1e9+1;
const int mod9 = 998244353;
const int mod1 = (int)1e9+7;
struct Edge { int to; long long cost; int from; };
bool compe(const Edge &e,const Edge &e2){ return e.cost < e2.cost; }
using Graph = vector<vector<int>>;
using SGraph = vector<set<ll>>;
template <class T>
int siz(T& a){return (int)a.size();}
ll squa(ll a){ return a*a; }
double torad(double x){ return x*(acos(-1)/180.0); }
ll cross(ll ax,ll ay,ll bx,ll by){ return ax*by-ay*bx; }
ll mceil(ll a,ll b){ return (a+b-1)/b; }

int main(){
    int N,Q; cin >> N >> Q;
    vector<int> A(N),B(Q);
    rep(i,N) cin >> A[i];
    rep(i,Q) cin >> B[i];
    
    vector<vector<pair<int,int>>> G(N*Q+N+1);
    rep(j,Q){
        rep(i,N){
            G[j*N+i].emplace_back(j*N+i+1,1);
            G[j*N+i+1].emplace_back(j*N+i,1);
        }
        rep(i,N){
            if(A[i] != B[j]) continue;
            if(j != Q-1) G[j*N+i].emplace_back((j+1)*N+i,0);
            else G[j*N+i].emplace_back(N*Q,0);
        }
    }

    vector<int> dist(N*Q+1,iinf);
    deque<int> D;
    D.push_back(0);
    dist[0] = 0;

    while(siz(D)){
        int v = D.front(); D.pop_front();
        for(auto [nv,c] : G[v]){
            int d = dist[v]+c;
            if(d < dist[nv]){
                dist[nv] = d;
                if(c) D.push_back(nv);
                else D.push_front(nv);
            }
        }
    }
    
    cout << dist[N*Q];
}