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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pb push_back
#define mp make_pair
#define all(a) begin(a),end(a)
#define FOR(x,val,to) for(int x=(val);x<int((to));++x)
#define FORE(x,val,to) for(auto x=(val);x<=(to);++x)
#define FORR(x,arr) for(auto &x: arr)
#define FORS(x,plus,arr) for(auto x = begin(arr)+(plus); x != end(arr); ++x)
#define FORREV(x,plus,arr) for(auto x = (arr).rbegin()+(plus); x !=(arr).rend(); ++x)
#define REE(s_) {cout<<s_<<'\n';exit(0);}
#define GET(arr) for(auto &i: (arr)) sc(i)
#define whatis(x) cerr << #x << " is " << (x) << endl;
#define e1 first
#define e2 second
#define INF 0x7f7f7f7f
typedef std::pair<int,int> pi;
typedef std::vector<int> vi;
typedef std::vector<std::string> vs;
typedef int64_t ll;
typedef uint64_t ull;
#define umap unordered_map
#define uset unordered_set
using namespace std;
using namespace __gnu_pbds;

#ifdef ONLINE_JUDGE
#define whatis(x) ;
#endif
#ifdef _WIN32
#define getchar_unlocked() _getchar_nolock()
#define _CRT_DISABLE_PERFCRIT_LOCKS
#endif
template<class L, class R> ostream& operator<<(ostream &os, map<L, R> P) { for(auto const &vv: P)os<<"("<<vv.first<<","<<vv.second<<")"; return os; }
template<class T> ostream& operator<<(ostream &os, set<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
template<class T> ostream& operator<<(ostream &os, vector<T> V) { os<<"[";for(auto const &vv:V)os<<vv<<","; os<<"]"; return os; }
template<class L, class R> ostream& operator<<(ostream &os, pair<L, R> P) { os<<"("<<P.first<<","<<P.second<<")"; return os; }
inline int fstoi(const string &str){auto it=str.begin();bool neg=0;int num=0;if(*it=='-')neg=1;else num=*it-'0';++it;while(it<str.end()) num=num*10+(*it++-'0');if(neg)num*=-1;return num;}
inline void getch(char &x){while(x = getchar_unlocked(), x < 33){;}}
inline void getstr(string &str){str.clear(); char cur;while(cur=getchar_unlocked(),cur<33){;}while(cur>32){str+=cur;cur=getchar_unlocked();}}
template<typename T> inline bool sc(T &num){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){if(c == EOF) return false;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; return true;}template<typename T, typename ...Args> inline void sc(T &num, Args &...args){ bool neg=0; int c; num=0; while(c=getchar_unlocked(),c<33){;} if(c=='-'){ neg=1; c=getchar_unlocked(); } for(;c>47;c=getchar_unlocked()) num=num*10+c-48; if(neg) num*=-1; sc(args...); }
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; //s.find_by_order(), s.order_of_key() <- works like lower_bound
template<typename T> using ordered_map = tree<T, int, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define N 1000001

int ret;
int n;

int root;
int p[N], adj[N][2];
int h[N];
bool fixd[N];

void l_rot(int v);
void r_rot(int v);

void r_rot(int v){
    /* if(adj[v][1]){ */
    if(adj[v][1] != -1){
        l_rot(adj[v][1]);
    }
    /* assert(adj[v][1] == -1); */
    /* if(p[v] != -1 && p[p[v]] != -1 && p[p[v]] > p[v]){ */
    if(p[v] != -1 && p[p[v]] != -1 && !fixd[p[p[v]]] && p[p[v]] > p[v]){
        r_rot(p[v]);
    }
    /* assert(p[v] == -1 || p[p[v]] == -1 || fixd[p[p[v]]] || p[p[v]] < p[v]); */
    adj[v][1] = p[v];
    // forgot to wyw adj p[v]
    adj[p[v]][0] = -1;
    /* assert(p[v] != v); */
    /* swap(p[v], p[p[v]]); */
    // omg, forgot to update adj of p[p[v]]
    int wppv = p[p[v]];
    if(wppv != -1){
        if(v < wppv)
            adj[wppv][0] = v;
        else
            adj[wppv][1] = v;
    }
    p[p[v]] = v;
    p[v] = wppv;
    ++ret;
}

void l_rot(int v){
    /* if(adj[v][0]){ */
    if(adj[v][0] != -1){
        r_rot(adj[v][0]);
    }
    /* assert(adj[v][0] == -1); */
    /* if(p[v] != -1 && p[p[v]] != -1 && p[p[v]] < p[v]){ */
    if(p[v] != -1 && p[p[v]] != -1 && !fixd[p[p[v]]] && p[p[v]] < p[v]){
        l_rot(p[v]);
    }
    /* assert(p[v] == -1 || p[p[v]] == -1 || p[p[v]] < p[v]); */
    /* assert(p[v] == -1 || p[p[v]] == -1 || p[p[v]] > p[v]); */
    /* assert(p[v] == -1 || p[p[v]] == -1 || fixd[p[p[v]]] || p[p[v]] > p[v]); */
    adj[v][0] = p[v];
    // forgot to wyw adj p[v]
    adj[p[v]][1] = -1;
    /* assert(p[v] != v); */
    // omg xd
    // przeciez to co napisalem powyzej wcale nie było swapem wtf
    /* swap(p[v], p[p[v]]); */
    /* assert(p[v] != v); */
    int wppv = p[p[v]];
    if(wppv != -1){
        if(v < wppv)
            adj[wppv][0] = v;
        else
            adj[wppv][1] = v;
    }
    p[p[v]] = v;
    p[v] = wppv;
    ++ret;
}

void rot(int v){
    if(p[v] == -1)
        return;
    if(p[v] < v)
        l_rot(v);
    else
        r_rot(v);
    /* FOR(i,0,n){ */
    /*     whatis(i) */
    /*     whatis(adj[i][0]) */
    /*     whatis(adj[i][1]) */
    /*     whatis(p[i]) */
    /* } */
}

int rootorg;
int porg[N];
int adjorg[N][2];

void pre(int v, int hh){
    /* whatis(v) */
    if(v == -1)
        return;
    h[v] = hh;
    pre(adj[v][0], hh + 1);
    pre(adj[v][1], hh + 1);
}

// replace with segtree i guess?
// pls no lazy propagation though
// może spamiętywanie, i while != upd?
// jak w dsu?
int whh(int v){
    /* whatis(v) */
    // forgot to memset p
    // opt as if it was needed
    if(fixd[v])
        return h[v];
    return h[v] = (p[v] == -1 ? 0 : whh(p[v]) + 1);
}

void rec(int v, int hh){
    if(v == -1)
        return;
    /* whatis(v) */
    /* int p = -1; */
    /* int cnt = 0; */
    while(whh(v) != hh){
    // equivalent surely, but no chance of performance issue
    /* while(p[v] != -1 && !fixd[p[v]]){ */
    // -> jednak nie
    // -> pls niech to co mam bedzie ok
        /* ++cnt; */
        /* whatis(whh(v)) */
        // not so true
        /* if(p == -1){ */
        /*     p = whh(v); */
        /* } */
        /* else{ */
        /*     assert(p == whh(v)+1); */
        /*     --p; */
        /* } */
        /* whatis("x") */
        /* whatis(whh(v)) */
        /* assert(whh(v) > hh); */
        rot(v);
    }
    // hmmm
    /* assert(cnt <= 5); */
    fixd[v] = 1;
    rec(adjorg[v][0], hh + 1);
    rec(adjorg[v][1], hh + 1);
}

int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    sc(n);
    memset(adj,-1,n<<3);
    memset(adjorg,-1,n<<3);
    memset(p,-1,n<<2);
    memset(porg,-1,n<<2);
    int cr;
    FOR(i,0,n){
        sc(cr);
        --cr;
        // gj on not setting adj
        if(cr == -2){
            root = i;
        }
        else{
            p[i] = cr;
            if(i < p[i])
                adj[p[i]][0] = i;
            else
                adj[p[i]][1] = i;
        }
    }
    /* FOR(i,0,n){ */
    /*     whatis(i) */
    /*     whatis(adj[i][0]) */
    /*     whatis(adj[i][1]) */
    /*     whatis(p[i]) */
    /* } */
    /* exit(0); */
    FOR(i,0,n){
        sc(cr);
        --cr;
        if(cr == -2){
            rootorg = i;
        }
        else{
            porg[i] = cr;
            if(i < porg[i])
                adjorg[porg[i]][0] = i;
            else
                adjorg[porg[i]][1] = i;
        }
    }
    /* assert(0); */
    pre(root, 0);
    rec(rootorg, 0);
    cout << ret << '\n';
    /* FOR(i,0,n){ */
    /*     whatis(i) */
    /*     whatis(adj[i][0]) */
    /*     whatis(adj[i][1]) */
    /*     whatis(p[i]) */
    /* } */
}