#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e3+7;
char a[maxn],b[maxn];
int dp[maxn][maxn];
void Dp() {
    int n = strlen(a);
    int m = strlen(b);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (a[i] == b[j])
                dp[i + 1][j + 1] = dp[i][j] + 1;
            else
                dp[i + 1][j + 1] = max(dp[i][j + 1], dp[i + 1][j]);
        }
    }
}
int main() {
    int n, m;
    cin >> n >> m;
    cin >> a >> b;
    Dp();
    cout << dp[n][m] << endl;
    return 0;
}