#include <iostream>

using namespace std;

int n, a[1000001];
int a1[1000001];
int main(){
// 	freopen("input.txt", "r", stdin);
// 	freopen("output.txt", "w", stdout);

	int ans = 0;
	cin >> n;
	for (int i = 1; i <= n; ++i)
	{	
		int x;
		cin >> x;
		if (a[x] > 0)
		{
			a1[x] = i - a[x];
		}else{
			a[x] = i;
		}
	}
	

	int mx = 0;
	for (int i = 0; i < n; ++i)
	{	
		//cout << a1[i] << endl;
		if (a1[i] > 1)
		{
			mx = max(mx, a1[i]);
		}
	}

	cout << mx + 1;






	return 0;
}