#include <bits/stdc++.h>
using namespace std;

using i64 = long long;

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    auto solve = [&]() {
        int n, m;
        cin >> n >> m;

        vector<vector<pair<int, int>>> g(n + 1);

        for (int i = 1; i <= n; i++) {
            int x;
            cin >> x;
            int sz = min(m, n - i + 1);
            for (int j = 1; j <= sz; j++) {
                int y;
                cin >> y;
                g[i - 1].emplace_back(i + j - 1, x - y);
            }
        }

        vector<i64> dp(n + 1, 1e18);
        dp[0] = 0;

        for (int u = 0; u < n; u++) {
            for (auto [v, w] : g[u]) {
                dp[v] = min(dp[v], dp[u] + w);
            }
        }

        cout << dp[n] << '\n';
    };
    
    solve();
    
    return 0;
}