#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define drep(i,j,n) for(int i=0;i<(int)(n-1);i++)for(int j=i+1;j<(int)(n);j++)
#define trep(i,j,k,n) for(int i=0;i<(int)(n-2);i++)for(int j=i+1;j<(int)(n-1);j++)for(int k=j+1;k<(int)(n);k++)
#define codefor int test;scanf("%d",&test);while(test--)
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define yes(ans) if(ans)printf("yes\n");else printf("no\n")
#define Yes(ans) if(ans)printf("Yes\n");else printf("No\n")
#define YES(ans) if(ans)printf("YES\n");else printf("NO\n")
#define vector1d(type,name,...) vector<type>name(__VA_ARGS__)
#define vector2d(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define vector3d(type,name,h,w,...) vector<vector<vector<type>>>name(h,vector<vector<type>>(w,vector<type>(__VA_ARGS__)))
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
const int MOD=1000000007;
const int MOD2=998244353;
const int INF=1<<30;
const ll INF2=(ll)1<<60;
//入力系
void scan(int& a){scanf("%d",&a);}
void scan(long long& a){scanf("%lld",&a);}
template<class T,class L>void scan(pair<T, L>& p){scan(p.first);scan(p.second);}
template<class T> void scan(T& a){cin>>a;}
template<class T> void scan(vector<T>& vec){for(auto&& it:vec)scan(it);}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){scan(head);in(tail...);}
//出力系
void print(const int& a){printf("%d",a);}
void print(const long long& a){printf("%lld",a);}
void print(const double& a){printf("%.15lf",a);}
template<class T,class L>void print(const pair<T, L>& p){print(p.first);putchar(' ');print(p.second);}
template<class T> void print(const T& a){cout<<a;}
template<class T> void print(const vector<T>& vec){if(vec.empty())return;print(vec[0]);for(auto it=vec.begin();++it!= vec.end();){putchar(' ');print(*it);}}
void out(){putchar('\n');}
template<class T> void out(const T& t){print(t);putchar('\n');}
template <class Head, class... Tail> void out(const Head& head,const Tail&... tail){print(head);putchar(' ');out(tail...);}
//デバッグ系
template<class T> void dprint(const T& a){cerr<<a;}
template<class T> void dprint(const vector<T>& vec){if(vec.empty())return;cerr<<vec[0];for(auto it=vec.begin();++it!= vec.end();){cerr<<" "<<*it;}}
void debug(){cerr<<endl;}
template<class T> void debug(const T& t){dprint(t);cerr<<endl;}
template <class Head, class... Tail> void debug(const Head& head, const Tail&... tail){dprint(head);cerr<<" ";debug(tail...);}
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
ll updivide(ll a,ll b){if(a%b==0) return a/b;else return (a/b)+1;}
template<class T> void chmax(T &a,const T b){if(b>a)a=b;}
template<class T> void chmin(T &a,const T b){if(b<a)a=b;}

int main(){
    INT(n);
    int ans=0;
    vector<int> s(n),t(n);
    vector2d(int,mat,n,n,-1);
    in(s,t);
    rep(i,n){
        if(s[i]==0){
            rep(j,n)mat[i][j]=0;
        }
        if(s[i]==2){
            rep(j,n)mat[i][j]=1;
        }
        if(t[i]==0){
            rep(j,n)mat[j][i]=0;
        }
        if(t[i]==2){
            rep(j,n)mat[j][i]=1;
        }
    }
    vector<int> x,y;
    bool h;
    rep(i,n){
        if(s[i]==1){
            h=false;
            rep(j,n){
                if(mat[i][j]==1){
                    h=true;
                    break;
                }
            }
            if(!h)y.push_back(i);
        }
        if(t[i]==1){
            h=false;
            rep(j,n){
                if(mat[j][i]==1){
                    h=true;
                    break;
                }
            }
            if(!h)x.push_back(i);
        }
    }
    set<int> usedy,usedx;
    rep(i,y.size()){
        rep(j,x.size()){
            if(!usedy.count(y[i])&&!usedx.count(x[j])&&mat[y[i]][x[j]]==-1){
                mat[y[i]][x[j]]=1;
                usedy.insert(y[i]);
                usedx.insert(x[j]);
            }
        }
    }
    rep(i,x.size()){
        rep(j,n){
            if(!usedx.count(x[i])&&mat[j][x[i]]==-1){
                mat[j][x[i]]=1;
                break;
            }
        }
    }
    rep(i,y.size()){
        rep(j,n){
            if(!usedy.count(y[i])&&mat[y[i]][j]==-1){
                mat[y[i]][j]=1;
                break;
            }
        }
    }
    rep(i,n){
        rep(j,n){
            if(mat[i][j]==-1)mat[i][j]=0;
            ans+=mat[i][j];
        }
    }
    out(ans);
}