#include <bits/stdc++.h>
using namespace std;
int dp[5002][7];
int dp2[5002][5002];
int dp3[5002];
int a[5002];
int n;
vector<int> v;
int mp[100002];
int main() {
  memset(mp, -1, sizeof(mp));
  cin >> n;
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    v.push_back(a[i]);
  }
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
  for (int i = 0; i < v.size(); i++) {
    mp[v[i]] = i;
  }
  for (int i = 0; i < n; i++) {
    int f = 1;
    for (int k = 0; k < i; k++) {
      int ne = dp[k][a[i] % 7];
      if (mp[a[i] - 1] != -1) {
        ne = max(ne, dp2[k][mp[a[i] - 1]]);
      }
      if (mp[a[i] + 1] != -1) {
        ne = max(ne, dp2[k][mp[a[i] + 1]]);
      }
      ne++;
      dp[k][a[i] % 7] = max(dp[k][a[i] % 7], ne);
      dp2[k][mp[a[i]]] = max(dp2[k][mp[a[i]]], ne);
      dp[i][a[k] % 7] = max(dp[i][a[k] % 7], ne);
      dp2[i][mp[a[k]]] = max(dp2[i][mp[a[k]]], ne);
      f = max(f, ne);
    }
    dp3[i] = 1;
    for (int k = 0; k < i; k++) {
      if (a[k] % 7 == a[i] % 7 || abs(a[i] - a[k]) == 1) {
        dp3[i] = max(dp3[i], dp3[k] + 1);
      }
    }
    for (int k = 0; k < i; k++) {
      dp[k][a[i] % 7] = max(dp[k][a[i] % 7], dp3[k] + 1);
      dp2[k][mp[a[i]]] = max(dp2[k][mp[a[i]]], dp3[k] + 1);
      dp[i][a[k] % 7] = max(dp[i][a[k] % 7], dp3[k] + 1);
      dp2[i][mp[a[k]]] = max(dp2[i][mp[a[k]]], dp3[k] + 1);
    }
  }
  int ans = 2;
  for (int i = 0; i < 5002; i++) {
    for (int j = 0; j < 5002; j++) {
      ans = max(ans, dp2[i][j]);
    }
  }
  cout << ans << endl;
  return 0;
}
