#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=n-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,-1,0,1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

int main(){
    ll n;cin >> n;
    vvl g(n,vl(n,-1));
    vl s(n),t(n);
    rep(i,n)cin >> s[i];rep(i,n)cin >> t[i];
    rep(i,n){
        if(s[i]==0){
            rep(j,n)g[i][j]=0;
        }
        if(s[i]==2){
            rep(j,n)g[i][j]=1;
        }
    }
    rep(i,n){
        if(t[i]==0){
            rep(j,n)g[j][i]=0;
        }
        if(t[i]==2){
            rep(j,n)g[j][i]=1;
        }
    }
    rep(i,n){
        rep(j,n){
            if(g[i][j]!=-1)continue;
            bool ok=true;
            rep(k,n)if(g[k][j]==1)ok=false;
            rep(k,n)if(g[i][k]==1)ok=false;
            if(ok)g[i][j]=1;
        }
    }
    rep(i,n){
        rep(j,n){
            if(g[i][j]!=-1)continue;
            bool oka=true,okb=true;
            rep(k,n)if(g[k][j]==1)oka=false;
            rep(k,n)if(g[i][k]==1)okb=false;
            if(oka||okb)g[i][j]=1;
            else g[i][j]=0;
        }
    }
    ll ans=0;
    rep(i,n){
        rep(j,n){
            ans+=g[i][j];
        }
        //cout << endl;
    }
    cout << ans <<endl;
}