#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(ri,n) for(int ri = (int)(n-1); ri >= 0; ri--)
#define rep2(i,x,n) for(int i = (int)(x); i < (int)(n); i++)
#define rrep2(ri,x,n) for(int ri = (int)(n-1); ri >= (int)(x); ri--)
#define repit(itr,x) for(auto itr = x.begin(); itr != x.end(); itr++)
#define rrepit(ritr,x) for(auto ritr = x.rbegin(); ritr != x.rend(); ritr++)
#define ALL(x) x.begin(), x.end()
using ll = long long;
using namespace std;

int main(){
  int n;
  cin >> n;
  vector<int> s(n);
  rep(i, n) cin >> s.at(i);
  vector<int> t(n);
  rep(i, n) cin >> t.at(i);
  int s2 = 0, s1 = 0, s0 = 0;
  int ans = 0;
  rep(i, n){
    if(s.at(i) == 2){
      s2++;
      ans += n;
    }else if(s.at(i) == 1){
      ans++;
      s1++;
    }else s0++;
  }
  cerr << ans << endl;
  rep(i, n){
    if(t.at(i) == 2){
      int p = n - s2;
      if(s1 - p >= 0) s1 -= p;
      else{
        ans += p - s1;
        s1 = 0;
      }
    }else if(t.at(i) == 1){
      if(s2 > 0) continue;
      if(s1 > 0) s1--;
      else ans++;
    }
  }
  cout << ans << endl;
  return 0;
}