#include<bits/stdc++.h>

using namespace std;

const int maxn = 1e3+;

char a[maxn],b[maxn];

int dp[maxn][maxn];

void Dp() {

    int n = strlen(a);

    int m = strlen(b);

    for (int i = ; i < n; i++) {

        for (int j = ; j < m; j++) {

            if (a[i] == b[j])

                dp[i + ][j + ] = dp[i][j] + ;

            else

                dp[i + ][j + ] = max(dp[i][j + ], dp[i + ][j]);

        }

    }

}

int main() {

    int n, m;

    cin >> n >> m;

    cin >> a >> b;

    Dp();

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

    return ;

}