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

#ifdef _RUTHEN
#include <debug.hpp>
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, M;
    cin >> N >> M;
    V<V<ll>> D(N, V<ll>(M));
    rep(i, N) {
        rep(j, M) cin >> D[i][j];
        sort(D[i].begin(), D[i].end());
    }
    const ll INF = 1LL << 60;
    V<ll> dp(M, 0);
    rep(i, N - 1) {
        V<V<pair<int, int>>> G(M + 1);
        rep(j, M) {
            int lb = lower_bound(D[i + 1].begin(), D[i + 1].end(), D[i][j]) - D[i + 1].begin();
            G[lb].push_back({1, j});
            int ub = lower_bound(D[i + 1].begin(), D[i + 1].end(), D[i][j] + dp[j]) - D[i + 1].begin();
            G[ub].push_back({2, j});
            G[ub].push_back({3, j});
        }
        V<ll> np(M);
        multiset<ll> S1;
        ll S2 = INF;
        S1.insert(INF);
        rep(j, M) {
            for (auto [t, k] : G[j]) {
                if (t == 1) {
                    S1.insert(dp[k]);
                } else if (t == 2) {
                    S1.extract(dp[k]);
                } else {
                    S2 = min(S2, -D[i][k]);
                }
            }
            np[j] = min({*S1.begin(), D[i + 1][j] + S2, INF});
        }
        swap(dp, np);
    }
    ll ans = *min_element(dp.begin(), dp.end());
    if (ans == INF) ans = -1;
    cout << ans << '\n';
    return 0;
}