Playlist

  #include <bits/stdc++.h>
  using namespace std;

  #define cin(vec) for(auto& i : vec) cin >> i
  #define cin_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> vec[i][j]; j++);
  #define cout(vec) for(auto& i : vec) cout << i << " "; cout << "\n";
  #define cout_2d(vec, n, m) for(int i = 0; i < n; i++, cout << "\n") for(int j = 0; j < m && cout << vec[i][j] << " "; j++);
  #define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
  #define fixed(n) cout << fixed << setprecision(n);
  #define ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
  #define fill(vec, value) memset(vec, value, sizeof(vec));
  #define Num_of_Digits(n) ((int)log10(n)+1)
  #define all(vec) vec.begin(),vec.end()
  #define rall(vec) vec.rbegin(),vec.rend()
  #define sz(x) int(x.size())
  #define fi first
  #define se second
  #define Pair pair < int, int >
  #define ll long long
  #define ull unsigned long long
  #define Mod  1'000'000'007
  #define INF 2'000'000'000
  #define PI acos(-1)

  void Code_Crush(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    #ifndef ONLINE_JUDGE
      freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
    #endif
  }

  int main(){
      Code_Crush();
      int n, Max = -INF;                                    cin >> n;
      vector <int> nums(n);
      map <int, bool> occ;
      cin(nums);
      int r = 0, l = 0;
      while(r < n){
        while(occ[nums[r]]) occ[nums[l++]] = false;
        occ[nums[r]] = true;
        Max = max(Max, r - l + 1);
        r++;
      }
      cout << Max;
      return 0;
  }