#include<bits/stdc++.h>

//#define LOCAL
#ifdef LOCAL
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#endif
using i64 = long long;
std::ostream& operator<<(std::ostream& o, std::vector<int>& a) {
    for (auto& x : a) o << x << ' ';
    return o;
}
class oper {
public:
    int operator()(int x)const {
        return x;
    }
};
void solve() {
    int n, m;
    std::cin >> n >> m;
    std::vector<int> a(n+1), b(m+1);
    std::string s1, s2;
    std::cin >> s1 >> s2;
    std::transform(s1.begin(), s1.end(), a.begin() + 1, oper());
    std::transform(s2.begin(), s2.end(), b.begin() + 1, oper());
    std::vector<std::vector<int>> dp(n + 1, std::vector<int>(m + 1));
    i64 cnt = 0;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            dp[i][j] = std::max(dp[i][j - 1], dp[i - 1][j]);
            if (a[i] == b[j]) {
                dp[i][j] = std::max({ dp[i][j],dp[i-1][j-1]+1});
            }
            cnt = std::max(cnt, 1LL*dp[i][j]);
        }
    }
    //for (int i = 1; i <= n; ++i) {
    //  for (int j = 1; j <= m; ++j) {
    //      std::cout << dp[i][j];
    //  }
    //  std::cout << '\n';
    //}
    std::cout << cnt << '\n';
}
auto main() -> signed {

    std::cin.tie(nullptr)->sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(2);
    solve();
    return 0;
}