#include<cstdio>
#include<iostream>
#include<queue>
using namespace std;
const int SIZEN=250010,INF=0x7fffffff/2;
typedef long long LL;
int N,M;
int A[SIZEN];
int B[SIZEN];
LL now=0;
void read()
{
	scanf("%d",&N);
	for(int i=1;i<=N;i++)
	{
		scanf("%d",&A[i]);
	}
	for(int i=1;i<=N;i++)
	{
		scanf("%d",&B[i]);
	}
}
priority_queue<int> Q;
void work()
{
	int ans=0;
	for(int i=1;i<=N;i++)
	{
		now+=A[i];
		if(now>=B[i])
		{
			Q.push(B[i]);
			now-=B[i];
			ans++;
		}
		else if(!Q.empty())
		{
			int tem=Q.top();Q.pop();
			if(tem>B[i]) now+=(LL)tem-B[i],tem=B[i];
			Q.push(B[i]);
		}
	}
	printf("%d\n",ans);
}
int main()
{
	freopen("wing.in","r",stdin);
	freopen("wing.out","w",stdout);
	read();
	work();
	return 0;
}