#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
#define INF (1LL << 60)
using namespace std;
typedef long long ll;
typedef vector<ll> vec;
typedef vector<vec> mat;

ll N, M;

mat mul(mat &A, mat &B) {
  mat C(M, vector<ll>(M, -INF));
  REP(i, 0, M) REP(j, 0, M) REP(k, 0, M) C[i][j] = max(C[i][j], A[i][k] + B[k][j]);
  return C;
}

mat pow(mat A, ll n) {
  mat B(M, vec(M, -INF));
  REP(i, 0, M) B[i][i] = 1;
  while(n > 0) {
    if(n & 1) B = mul(B, A);
    A = mul(A, A);
    n >>= 1;
  }
  return B;
}

int main(void) {
  cin >> N >> M;

  mat A(N, vec(N, -INF));
  REP(i, 0, M) REP(j, 0, M) cin >> A[j][i];

  A = pow(A, N - 1);

  ll ans = 0;
  REP(i, 0, M) REP(j, 0, M) ans = max(ans, A[i][j]);
  cout << ans - 1 << endl;
}