#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#define rep(i,n) for(int i = 0; i < n; i++) //[0,n)
using namespace std;
const int iinf = (int)1e9+1;
struct Edge { int to; long long cost; int from; };
bool compe(const Edge &e,const Edge &e2){ return e.cost < e2.cost; }
template <class T>
int siz(T& a){return (int)a.size();}

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+1);
    rep(j,Q){
        rep(i,N){
            if(i == N-1) continue;
            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];
}