#include<cstdio>
#include<algorithm>
long long f[311111]={};long long g[311111]={};int tou,wei,n,ans=0;long long temp=0;
int main()
{
	freopen("wing.in","r",stdin);
	freopen("wing.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)scanf("%lld",&f[i]);
	for(int i=1;i<=n;i++)scanf("%lld",&g[i]);
	std::sort(g+1,g+n+1);tou=1,wei=n;
	for(int i=1;i<=n;i++){
		temp+=f[i];
		if(temp>=g[tou]) temp-=g[tou],tou++,ans++;
		else wei--;
	}
	printf("%d\n",ans);
	return 0;
}