#include <bits/stdc++.h>
//#include "atcoder/all"
typedef long long int ll;
using namespace std;
// using namespace atcoder;
#define MAXA 1000001
int last[MAXA];
int main() {
    int n;
    cin >> n;
    ll a[n + 1];
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for (int i = 1; i < MAXA; i++) {
        last[i] = 0;
    }
    int ret = 0;
    int now = 1;
    for (int i = 1; i <= n; i++) {
        now = min(now, i - last[a[i]]);
        last[a[i]] = i;
        if (now > ret) ret = now;
        now++;
    }
    cout << ret << endl;
    return 0;
}