#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=250008;
const int mod=1e9+7;
int a[N],b[N],Max[N];
int main(){
   int n;
   while(scanf("%d",&n)!=EOF){
    for(int i=1;i<=n;++i) scanf("%d",&a[i]),a[i]-=i;
    for(int i=1;i<=n;++i) scanf("%d",&b[i]);
    Max[n]=a[n];
    for(int i=n-1;i>=1;--i) Max[i]=max(Max[i+1],a[i]);
    sort(b+1,b+n+1);
    int ans1=Max[b[1]]-n-1,ans=Max[b[1]];
    for(int i=2;i<=n;++i)  ans=(ans+max(Max[b[i]],ans1))%mod;
    printf("%d\n",ans);
   }
}