#include using namespace std; const int N = 3010; int a[N], b[N]; int f[N][N]; int res; // O(n^2) int main() { int n; cin >> n; for (int i = 1; i <= n; i++) cin >> a[i]; for (int i = 1; i <= n; i++) cin >> b[i]; for (int i = 1; i <= n; i++) { int maxv = 1; for (int j = 1; j <= n; j++) { f[i][j] = f[i - 1][j]; if (a[i] == b[j]) f[i][j] = maxv; if (a[i] > b[j]) maxv = max(maxv, f[i - 1][j] + 1); } } for (int i = 1; i <= n; i++) res = max(res, f[n][i]); printf("%d\n", res); return 0; }