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

int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  for (int i = 0; i < N; i++) cin >> A.at(i);
  set<int> SE;
  int mx = 0;
  for (int l = 0, r = 0; r < N; r++) {
    if (SE.count(A.at(r))) {
      while (A.at(l) != A.at(r)) SE.erase(A.at(l++));
      SE.erase(A.at(l++));
    }
    SE.insert(A.at(r));
    mx = max(mx, r - l + 1);
  }
  cout << mx << "\n";
}