#include <bits/stdc++.h>
#define int long long
#define fast ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define lg2(n) (63-__builtin_clzll(n))
#define mask(n) (1LL << (n))
#define TASK ""
#define openfile();  if( fopen(TASK".inp", "r")){freopen(TASK".inp", "r", stdin);freopen(TASK".out", "w", stdout);}
#define lc(n) (n << 1)
#define rc(n) ((n << 1) | 1)

#define fi first
#define se second
#define FOR(i, l, r, k) for( int i = l; i <= r; i += k)
#define FOD(i, r, l, k) for( int i = r; i >= l; i -= k)

#define mii map<int,int>
#define umi unordered_map<int, int>
#define pii pair<int,int>
#define vi vector<int>

using namespace std;

const int oo = 1e18;
const int mod = 1e9 + 9;
const int nmax = 1e3 + 8;
const int base = 311;

int n, m, k, a[nmax], b[nmax], dp[nmax][nmax];

main(){
    fast;
    openfile();
    cin >> n >> m;
    int ans = 0;
    FOR(i, 1, n, 1) cin >> a[i];
    FOR(i, 1, m, 1) cin >> b[i];
//    dp[0][0] = 1;
    for(int i = 1; i <= n; ++i){
        for(int j = 1; j <= m; ++j){
            if(a[i] == b[j]){
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }
            else dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
//                ans = max(ans, dp[i][j]);
        }
    }
    cout << dp[n][m];
}