#include<bits/stdc++.h>
using namespace std;
int n,a[500010],ans=0;
int main(){
	freopen("c.in","r",stdin);
	freopen("c.ans","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=1;i<=n;i++){
    	int it=i+1;
    	while(it<=n){
    		if(a[it]/2>=a[i])break;
    		it++;
    	}
    	ans+=n-it+1;
    }
    cout<<ans<<endl;
}

对拍 1200 个也没错？？？