#include <bits/stdc++.h>
using namespace std;
bool isp[300005];
void sv() {
  long long i, j;
  memset(isp, true, sizeof(isp));
  isp[1] = false;
  for (i = 2; i * i < 300005; i++) {
    if (isp[i]) {
      for (j = i * i; j < 300005; j += i) isp[j] = false;
    }
  }
}
long long powr(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % 1000000007;
    a = (a * a) % 1000000007;
    b >>= 1;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, i, j, a[300005], x, y;
  map<long long, vector<long long> > mp;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    mp[a[i]].push_back(i);
  }
  long long ans = 0;
  auto it = mp.begin();
  while (it != mp.end()) {
    (it->second).push_back(n);
    it++;
  }
  auto itr = mp.begin();
  while (itr != mp.end()) {
    long long l = (itr->second).size();
    for (i = l - 1; i > 0; i--) {
      if ((itr->second)[i] != (itr->second)[i - 1] + 1) {
        long long tmp = (itr->second)[i] - (itr->second)[0] - 1;
        if (tmp > ans) {
          ans = tmp;
        } else
          break;
      }
    }
    itr++;
  }
  cout << ans;
  return 0;
}
