#include <iostream>
#include <stdio.h>

using namespace std;


const int N = 1010;

int n, m;
char a[N], b[N];
int dp[N][N];

int main()
{
    scanf("%d%d", &n, &m);
    scanf("%s", a + 1);

    scanf("%s", b + 1);


    //cout << a <<endl;
    //cout << b << endl;

    for(int i = 1; i <= n; i++)
    {
        for(int k = 1; k <= m; k++)
        {

            dp[i][k] = max(dp[i - 1][k], dp[i][k - 1]);
            if(a[i] == b[k])
            {
                dp[i][k] = max(dp[i - 1][k - 1] + 1, dp[i][k]);
            }



        }
    }

    cout << dp[n][m] << endl;


    return 0;
}