#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) FOR(i,0,n)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define PQ priority_queue
#define UM unordered_map
#define ALL(a) (a).begin(),(a).end()
#define MOD 1000000007
typedef vector<ll> vi;
typedef vector<vector<ll>> vvi;
const ll INF = (1ll << 30);
typedef pair<ll,ll> pii;
struct Edge{ ll s,t,c; };
typedef vector<vector<Edge>> Graph;
typedef vector<pii> vpii;
int main() {
  ll n,m; cin>>n>>m;
  vvi a(m,vi(m)); REP(i,m) REP(j,m) cin>>a[i][j];
  vvi dp(m,vi(n));
  FOR(i,1,n) {
    REP(j,m) {
      REP(k,m) {
        dp[j][i]=max(dp[j][i],dp[k][i-1]+a[k][j]);
      }
    }
  }
  ll ans=0; REP(i,m) ans=max(ans,dp[i][n-1]);
  cout<<ans<<endl;
}