#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>

#define max(a,b) ((a>b)?a:b)

int main(){

	FILE *input = fopen("cmlsc.in", "r");
	FILE *output = fopen("cmlsc.out", "w");

	int m, n;
	fscanf(input, "%d %d", &m, &n);

	int *v1 = (int*)malloc(m*sizeof(int));
	int *v2 = (int*)malloc(n*sizeof(int));
	for (int i = 1; i <= m; i++)
	{
		fscanf(input, "%d", &v1[i]);
	}
	for (int i = 1; i <= n; i++)
	{
		fscanf(input, "%d", &v2[i]);
	}

	int **C = (int**)malloc(n*sizeof(int*));
	for (int i = 0; i <= n; i++)
	{
		C[i] = (int*)malloc(m*sizeof(int));
	}
	for (int i = 0; i <= m; i++)
	{
		C[0][i] = 0;
	}
	for (int j = 0; j <= n; j++)
	{
		C[j][0] = 0;
	}
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= m; j++)
		{
			
			if (v1[i] == v2[j])
			{
				C[i][j] = C[i - 1][j - 1] + 1;
			}
			else{
				C[i][j] = max(C[i][j - 1], C[i - 1][j]);
			}
		}
	}

	//print  out the nr of the longest common subseq
	fprintf(output, "%d\n", C[m][n]);
	//print out the subsequence

	return 0;
}