#include <bits/stdc++.h>
using namespace std;
#include <atcoder/segtree>
using namespace atcoder;
using ll = long long;
using P = pair<int,int>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL <<62);
constexpr int INF = (1 << 30);
int op(int a, int b){ return min(a,b); }
int e(){ return INF; }
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,m;
    cin >> n >> m;
    vector<vector<int>> a(n, vector<int>(m));
    vector<int> v0(m, 0), vI(m, INF);
    vector<segtree<int,op,e>> dp(n, segtree<int,op,e>(vI));
    dp[0] = segtree<int,op,e>(v0);
    rep(i,n){
        rep(j,m) cin >> a[i][j];
        sort(all(a[i]));
    }
    rep(i,n-1){
        int now = 0, upd = -INF;
        priority_queue<asc(P)> pq;
        rep(j,m){
            while(now<m && a[i+1][j]>=a[i][now]){
                pq.push({dp[i].get(now)+a[i][now], now});
                now++;
            }
            while(pq.size() && pq.top().first<a[i+1][j]){
                dp[i].set(pq.top().second, INF);
                chmax(upd, a[i][pq.top().second]);
                pq.pop();
            }
            dp[i+1].set(j, min(a[i+1][j]-upd, dp[i].prod(0, now)));
        }
    }
    int ans = INF;
    rep(i,m) chmin(ans, dp[n-1].get(i));
    if(ans==INF) ans = -1;
    cout << ans << '\n';
    return 0;
}