#include <bits/stdc++.h>
//0 qian j ge
//1 hou j ge
#define INF 0x3f3f3f3f
int N,L,va[8009],c[8009],la[8009][8009],vc[70000009][2],v2[70000009][2],
su[8009],ff[8009][8009],su2[8009];
std::vector<int> t[8009];
int sv2(int n,int x,int y,int op);
int sv(int n,int x,int y,int op);
int fd(int n,int x,int y,int op) {
	int a=sv(n,x,y,op);
	if((n==N-1)||(x==c[n])) return a;
	int l1=0;
	if(x<c[n]) l1=t[n][x+1]-1;else l1=L;
	a=std::min(a,sv2(n,ff[n+1][l1],((op==0)?(y):(x-y)),op)+x);
	return a;
}
int sv2(int n,int x,int y,int op) {
	if(x<0) return INF;
	int id=x*(c[n]+1)+y+su2[n-1];
	if(v2[id][op]!=-1) return v2[id][op];
	int ans=sv2(n,x-1,y,op);
	for(int xx=x;xx<=x;xx++) {
		int l2=0,l1=0;
		if(x<c[n]) l1=t[n][x+1]-1;else l1=L;
		if(xx<c[n+1]) l2=t[n+1][xx+1]-1;else l2=L;
		//if(l2>l1) continue;
		int lim=l2;
		int tp1=la[lim][n],tp2=la[lim][n+1];
		int vv=va[n+1];
		if(op==1) vv-=std::min(y,tp1);
		else vv-=(std::max(tp1,y)-y);	
		if(vv<=0) {
			ans=std::min(ans,fd(n+1,xx,0,0));
		} else {
			int yy=vv;
			if(yy<=tp2) ans=std::min(ans,fd(n+1,xx,yy,0));	
			yy=vv+xx-std::min(xx,tp2);
			if(yy<=xx) ans=std::min(ans,fd(n+1,xx,yy,1));				
		}
	}
	return v2[id][op]=ans;
}
int sv(int n,int x,int y,int op) {
	int id=x*(c[n]+1)+y+su[n-1];
	if(n==N-1) {
		if(x<c[n]&&(x-y)<va[n+1]) return INF;
		return x;
	}
	if(vc[id][op]!=-1) {
		return vc[id][op];
	}
	int ans=INF;
	int limm=0;
	//if(x<c[n]) limm=std::max(c[n+1]-1,0);
	for(int xx=limm;xx<=c[n+1];xx++) {
		int l1=0,l2=0;
		if(xx<c[n+1]) l2=t[n+1][xx+1]-1;else l2=L;
		if(x<c[n]) l1=t[n][x+1]-1;else l1=L;
		int lim=std::min(l1,l2);
		int tp1=la[lim][n],tp2=la[lim][n+1];
		int vv=va[n+1];
		if(op==1) vv-=std::min(x-y,tp1);
		else vv-=(std::max(std::min(x,tp1),y)-y);	
		if((vv<=0)||(xx==c[n+1]&&x==c[n])) {
			ans=std::min(ans,fd(n+1,xx,0,0)+x);
		} else {
			int yy=vv;
			if(yy<=tp2) ans=std::min(ans,fd(n+1,xx,yy,0)+x);	
			yy=vv+xx-std::min(xx,tp2);
			if(yy<=xx) ans=std::min(ans,fd(n+1,xx,yy,1)+x);				
		}
	}
	return vc[id][op]=ans;
}
signed main(void) {
	memset(vc,-1,sizeof(vc));
	memset(v2,-1,sizeof(v2));
	scanf("%d",&N);
	for(int i=1;i<=N;i++) {
		scanf("%d",&va[i]);
		t[i].push_back(0);
	}
	scanf("%d",&L);
	for(int i=1;i<=L;i++) {
		int x;
		scanf("%d",&x);
		t[x].push_back(i);
		c[x]++;
		for(int j=1;j<=N;j++) {
			la[i][j]=la[i-1][j];
		}
		la[i][x]=t[x].size()-1;
	}
	for(int i=1;i<=N;i++) {
		int la=0;
		for(int j=0;j<=c[i];j++) {
			int l2=0;
			if(j<c[i]) l2=t[i][j+1]-1;else l2=L+1;
			for(int k=la;k<l2;k++) {
				ff[i][k]=j-1;
			}
			la=l2;
		}
	}
	for(int i=1;i<=N;i++) {
		su[i]=su[i-1]+(c[i]+1)*(c[i]+1);
		su2[i]=su2[i-1]+(c[i]+1)*c[i+1];
		assert(su2[i]<=70000000);
	}
	int ans=0x3f3f3f3f;
	for(int i=0;i<=c[1];i++) {
		for(int j=0;j<=i&&j<=va[1];j++) {
			if((i==c[1])||(j==va[1])) ans=std::min(ans,fd(1,i,j,0));
			if((i==c[1])||(j==va[1])) ans=std::min(ans,fd(1,i,j,1));
		}
	}
//	printf("%d\n",sv(4,0,0,0));
	printf("%d",L-ans);
}