This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
#define ll long long
#define rep(i,n,N) for(int i = n; i<=N; ++i)
#define rap(i,n,N) for(int i = n; i>=N; --i)
#define For(i,n,N) for(int i = n; i< N; ++i)
#define endl '\n'
#define pb push_back
#define all(x) x.begin(),x.end()
#define mems(x,y) memset(x,y,sizeof x)
#define ari(x) array<int,x>
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fi first
#define se second
const int MAX = 1e5 + 5;
mt19937 rng(time(NULL));
int n,x[MAX],y[MAX],cnt;
vector<int> v;
#define lc (id<<1)
#define rc ((id<<1)|1)
struct rmqSegtree{
	int tree[1<<18];
	int n,a,b;
	void build(int id,int le,int ri){
		if(le==ri){
			tree[id] = x[le];
			return;
		}
		int mid = le+ri>>1;
		build(lc,le,mid), build(rc,mid+1,ri);
		tree[id] = max(tree[lc], tree[rc]);
		return;
	}
	int que(int id,int le,int ri){
		if(le>b || ri<a)return 0;
		if(le>=a && ri<=b)return tree[id];
		int mid = le+ri>>1;
		return max(que(lc,le,mid), que(rc,mid+1,ri));
	}
	int que(int L,int R){
		a = L, b = R;
		return que(1,1,n);
	}
}rmq;
struct ansSegtree{
	int tree[1<<18];
	int n,val,a,b;
	void upd(int id,int le,int ri){
		if(le==ri){
			tree[id] = val;
			return;
		}
		int mid = le+ri>>1;
		if(a<=mid)upd(lc,le,mid);
		else upd(rc,mid+1,ri);
		tree[id] = max(tree[lc], tree[rc]);
		return;
	}
	int que(int id,int le,int ri){
		if(le>b || ri<a)return 0;
		if(le>=a && ri<=b)return tree[id];
		int mid = le+ri>>1;
		return max(que(lc,le,mid), que(rc,mid+1,ri));
	}
	int que(int L,int R){
		a = L, b = R;
		return que(1,1,n);
	}
	void upd(int pos,int _v){
		a = pos;
		val = _v;
		upd(1,1,n);
	}
}tree[2];
vector<int> z[MAX];
int main(){
//	freopen("input.4_j", "r", stdin);
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin>>n;
	rep(i,1,n)cin>>x[i], v.pb(x[i]);
	sort(all(v));
	v.erase(unique(all(v)), v.end());
	rep(i,1,n)x[i] = upper_bound(all(v), x[i]) - v.begin();
	auto it = v.begin();
	rep(i,1,n){
		cin>>y[i];
		it = lower_bound(all(v), y[i]);
		y[i] = it==v.end() || *it!=y[i] ? 0 : it-v.begin()+1;
	}
	
	rmq.n = tree[0].n = tree[1].n = n;
	rmq.build(1,1,n);
	rep(i,1,n)z[x[i]].pb(i);
	int pos,val,wot;
	rep(i,1,n){
		if(x[i]<=y[i]){
			it = lower_bound(all(z[y[i]]), i);
			pos = -1;
			if(it != z[y[i]].end()){
				pos = *it;
				val = max(tree[0].que(1,y[i]), tree[1].tree[1]) + (rmq.que(i,pos)==y[i]);
				tree[0].upd(y[i], val);
			}
			if(pos==i){
				tree[1].upd(y[i], val);
			}
			else if(it != z[y[i]].begin()){
				pos = *prev(it);
				tree[1].upd(y[i], tree[1].que(y[i],n) + (rmq.que(pos,i)==y[i]));
			}
		}
		tree[1].upd(x[i], max(tree[0].que(1,x[i]), tree[1].tree[1]));
	}
	cout<<max(tree[0].tree[1], tree[1].tree[1])<<endl;
	return 0;
}
Compilation message (stderr)
exam.cpp: In member function 'void rmqSegtree::build(int, int, int)':
exam.cpp:37:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   37 |   int mid = le+ri>>1;
      |             ~~^~~
exam.cpp: In member function 'int rmqSegtree::que(int, int, int)':
exam.cpp:45:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   45 |   int mid = le+ri>>1;
      |             ~~^~~
exam.cpp: In member function 'void ansSegtree::upd(int, int, int)':
exam.cpp:62:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   62 |   int mid = le+ri>>1;
      |             ~~^~~
exam.cpp: In member function 'int ansSegtree::que(int, int, int)':
exam.cpp:71:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   71 |   int mid = le+ri>>1;
      |             ~~^~~
exam.cpp: In function 'int main()':
exam.cpp:105:14: warning: unused variable 'wot' [-Wunused-variable]
  105 |  int pos,val,wot;
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