#include<cstdio>
#include<cstring>
#include<iostream>
#define mem(arr,arl) memset(arr,arl,siae)
using namespace std;
const int maxn=100010;
int len[maxn],h[maxn],ge[maxn];
int read(){
	int f=1,x=0;
	char ch=getchar();
	while ((ch<'0'||ch>'9')&&ch!='-')ch=getchar();
	if (ch=='-')f=-1;
	else x=ch-'0';
	ch=getchar();
	while (ch>='0'&&ch<='9') {
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*f;
}
int Find(int x,int l,int r){
	if(r<l)return l;
	int mid=(l+r)>>1;
	if(len[mid]>x)Find(x,mid+1,r);
	else Find(x,l,mid-1);
}
int MY(){
	freopen("lunch.in","r",stdin);
	freopen("lunch.out","w",stdout);
	len[0]=0x7f7f7f;
	int p;p=read();
	for(int i=1;i<=p;i++){	
		h[i]=read();
		if(!h[i])continue;
		int z=Find(h[i],0,p);
		ge[i]=z;
		len[z]=h[i];
	}
	int ans=0;
	for(int i=1;i<=p;i++)if(ans<ge[i])ans=ge[i];
	printf("%d\n",ans);
	return 0;
}
int YOU=MY();
int main(){;}