#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif
    int n;
    cin >> n;
    map<int, pair<int, int>> mp;
    for (int i = 0, x; i < n; ++i) {
        cin >> x;
        if (mp.find(x) == mp.end()) mp[x] = make_pair(i, i);
        else mp[x].second = i;
    }
    int ans = 0;
    for (auto &i : mp) ans = max(ans, i.second.second - i.second.first + 1);
    cout << ans << '\n';
    return 0;
}