#include <fstream>

using namespace std;
ifstream fin("cmlsc.in");
ofstream fout("cmlsc.out");

int matrice[1030][1030];

int LCS(int* s1, int* s2, int Ls1, int Ls2) {
	for (int i = 1; i <= Ls1; ++i) {
		for (int j = 1; j <= Ls2; ++j) {
			if (s1[i] == s2[j])
				matrice[i][j] = matrice[i - 1][j - 1] + 1;
			else {
				int maxim = matrice[i][j - 1];
				if (maxim < matrice[i - 1][j])
					maxim = matrice[i - 1][j];
				matrice[i][j] = maxim;
			}
		}
	}
	return matrice[Ls1][Ls2];
}
int main()
{
	int Ls1, Ls2, s1[1030], s2[1030];
	fin >> Ls1 >> Ls2;
	for (int i = 1; i <= Ls1; ++i)
		fin >> s1[i];
	for (int i = 1; i <= Ls2; ++i)
		fin >> s2[i];
	fout << LCS(s1, s2, Ls1, Ls2);
	return 0;
}