#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
typedef long long ll;
static const int INF = 1e8;

int main(void){
	int N;
	int a[3010],b[3010];
	cin >> N;
    rep(i,N){
    	cin >> a[i];
        a[i+N] = a[i];
     }
    rep(i,N){
    	cin >> b[i];
    	b[i+N] = b[i];
    }
    int ans = INF;
    rep(i,N){
    priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> pq;
    for(int j=0;j<N;++j){
     pq.push(make_pair(a[j],0));
    }
    for(int j = i; j < i + N;j++){
    	int llv=pq.top().first;
    	int t = pq.top().second;
    	pq.pop();
    	int lvup = b[j] /2;
    	pq.push(make_pair(llv + lvup,t+1));
    }
    int tmp = 0;
    while(!pq.empty()){
    	int t = pq.top().second;pq.pop();
    	tmp = max(tmp,t);
    }
    ans = min(ans,tmp);

}
cout << ans << endl;
return 0;
}