#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <class T, class U>
ostream& operator<<(ostream& o, const pair<T, U>& p) {
  o << "(" << p.first << "," << p.second << ")";
  return o;
}
template <class T>
ostream& operator<<(ostream& o, const vector<T>& v) {
  o << "[";
  for (T t : v) {
    o << t << ",";
  }
  o << "]";
  return o;
}
const int N = 5005;
int dp[N][N];
int mod[7];
int num[100001];
int main() {
  int n;
  cin >> n;
  vector<int> a(n + 1);
  for (int(i) = 0; (i) < (int)(n); ++(i)) {
    cin >> a[i + 1];
    --a[i + 1];
  }
  for (int i = 1; i <= n; ++i) {
    dp[i][0] = 1;
    for (int(j) = 0; (j) < (int)(i); ++(j)) {
      if ((a[i] % 7 == a[j] % 7) || (abs(a[j] - a[i]) == 1))
        dp[i][0] = max(dp[i][0], dp[j][0] + 1);
    }
    memset(mod, 0, sizeof(mod));
    memset(num, 0, sizeof(num));
    for (int(j) = 0; (j) < (int)(i); ++(j)) {
      mod[a[j] % 7] = max(mod[a[j] % 7], dp[i][j]);
      num[a[j]] = max(num[a[j]], dp[i][j]);
    }
    for (int j = i + 1; j <= n; ++j) {
      dp[j][i] = dp[i][0] + 1;
      dp[j][i] = max(dp[j][i], mod[a[j] % 7] + 1);
      dp[j][i] = max(dp[j][i], num[a[j] + 1] + 1);
      dp[j][i] = max(dp[j][i], num[a[j] - 1] + 1);
      mod[a[j] % 7] = max(mod[a[j] % 7], dp[j][i]);
      num[a[j]] = max(num[a[j]], dp[j][i]);
    }
  }
  int ans = 0;
  for (int(i) = 0; (i) < (int)(N); ++(i))
    for (int(j) = 0; (j) < (int)(N); ++(j)) ans = max(ans, dp[i][j]);
  cout << ans << endl;
  return 0;
}
