#include <bits/stdc++.h>
using namespace std;

signed main(){
  int N; cin >> N;
  vector< int > A( N );
  for( int i = 0; i < N; ++i )
    cin >> A[ i ];
  vector< int > B( N );
  for( int i = 0; i < N; ++i )
    cin >> B[ i ];
  int ans = 0x3f3f3f3f;
  for( int i = 0; i < N; ++i ){ // starting point of monster combat
    priority_queue< pair< int, int >, vector< pair< int, int > >, greater< pair< int, int > > > pq;
    for( int j = 0; j < N; ++j )
      pq.emplace( A[ j ], 0 );
    int max_rnd = 0;
    for( int j = i; ; j = ( j + 1 ) % N ){
      int lv, rnd; tie( lv, rnd ) = pq.top(); pq.pop();
      pq.emplace( lv + B[ j ] / 2, rnd + 1 );
      max_rnd = max( max_rnd, rnd + 1 );
      if( ( j + 1 ) % N == i )
        break;
    }
    ans = min( ans, max_rnd );
  }
  cout << ans << endl;
  return 0;
}