#include<bits/stdc++.h>

namespace IO
{
	template<typename Type>
	void read(Type &x){
		char ch=getchar();
		x=0;bool f=0;
		while(ch<'0'||ch>'9') f|=(ch=='-'),ch=getchar();
		while(ch>='0'&&ch<='9') x=((x<<1)+(x<<3)+(ch^48)),ch=getchar();
		x=f?-x:x;
	}
}

using namespace std;

#define N 500005
#define lson(x) (x<<1)
#define rson(x) (x<<1|1)
#define Judge(x) (tree[x].l<=r&&tree[x].r>=l)

int n,pos,ans;
int a[N],head[N],rdeg[N],dp[N],ret[N];

struct Edge
{
	int u,v,nxt;
}e[N];

void addEdge(int u,int v)
{
	e[++pos]={u,v,head[u]};
	head[u]=pos;
}

struct SegTree
{
	int l,r,maxval;
}tree[N<<2];

inline void pushup(int t)
{
	tree[t].maxval=max(tree[lson(t)].maxval,tree[rson(t)].maxval);
}

inline void Build(int t,int l,int r)
{
	tree[t]={l,r,1e9};
	if(l==r) return ;
	int mid=l+r>>1;
	Build(lson(t),l,mid);
	Build(rson(t),mid+1,r);
	pushup(t);
}

inline void update(int t,int idx,int val)
{
	if(idx==tree[t].l&&idx==tree[t].r){
		tree[t].maxval=val;
		return ;
	}
	if(tree[lson(t)].l<=idx&&tree[lson(t)].r>=idx) update(lson(t),idx,val);
	else update(rson(t),idx,val);
	pushup(t);
}

inline int query(int t,int l,int r)
{
	if(l>r) return 1e9;
	if(tree[t].l>=l&&tree[t].r<=r) return tree[t].maxval;
	int res=0;
	if(Judge(lson(t))) res=max(res,query(lson(t),l,r));
	if(Judge(rson(t))) res=max(res,query(rson(t),l,r));
	return res;
}

void toposort()
{
	queue<int> q1;
	q1.push(0);
	while(q1.size()){
		int u=q1.front();
		q1.pop();
		for(int i=head[u];i;i=e[i].nxt){
			int v=e[i].v;
			dp[v]=max(dp[v],dp[u]+1);
			rdeg[v]--;
			if(!rdeg[v]) q1.push(v);
		}
	}
}

int main()
{
	memset(ret,0x3f,sizeof ret);
	IO::read(n);
	for(int i=1;i<=n;i++) IO::read(a[i]);
	Build(1,1,n);
	for(int i=1;i<=n;i++){
		int pre=query(1,1,a[i]-1);
		if(pre>=1e9){
			addEdge(0,a[i]);
			update(1,a[i],1);
			ret[1]=min(ret[1],a[i]);
			rdeg[a[i]]++;
//			printf("%d->%d\n",0,a[i]);
			continue ;
		}
		int u=ret[pre];
//		printf("%d->%d\n",u,a[i]);
		addEdge(u,a[i]);
		update(1,a[i],pre+1);
		ret[pre+1]=min(ret[pre+1],a[i]);
		rdeg[a[i]]++;
	}
	toposort();
	for(int i=1;i<=n;i++) ans=max(ans,dp[i]);
	printf("%d",ans);
}