98pts，玄关，求条

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,ans=1;
struct Node{
    int x,y;
}arr[1000005];
deque<int> q;
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>arr[i].x>>arr[i].y;
    }
    int temp=0;
    q.push_back(1);
    for(int i=1;i<=n;i++){
        while(!q.empty() && arr[q.front()].x>arr[i].y){
        	temp=q.front();
        	q.pop_front();
		}
		if(!q.empty()){
			ans=max(ans,i-temp);
		}
		while(!q.empty() && arr[q.front()].x<=arr[i].x){
			q.pop_back();
		}
		q.push_back(i);
    }
    cout<<ans;
    return 0;
}