#include<iostream>
#include<algorithm>
using namespace std;
int N;
int cnt[1<<20];
int A[1<<17];
int ans;
main()
{
	cin>>N;
	int l=0,nc=0;
	for(int i=0;i<N;i++)
	{
		cin>>A[i];
		while(cnt[A[i]])
		{
			cnt[A[l++]]--;
			nc--;
		}
		nc++;
		cnt[A[i]]++;
		ans=max(ans,nc);
	}
	cout<<ans<<endl;
}