/*
Author: QAQAutomaton
Lang: C++
Code: F.cpp
Mail: lk@qaq-am.com
Blog: https://www.qaq-am.com/
*/
#include<bits/stdc++.h>
#define debug(...) fprintf(stderr,__VA_ARGS__)
#define DEBUG printf("Passing [%s] in LINE %d\n",__FUNCTION__,__LINE__)
#define Debug debug("Passing [%s] in LINE %d\n",__FUNCTION__,__LINE__)
#define all(x) x.begin(),x.end()
#define x first
#define y second
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
int inf;
const double eps=1e-8;
const double pi=acos(-1.0);
template<class T,class T2>int chkmin(T &a,T2 b){return a>b?a=b,1:0;}
template<class T,class T2>int chkmax(T &a,T2 b){return a<b?a=b,1:0;}
template<class T>T sqr(T a){return a*a;}
template<class T,class T2>T mmin(T a,T2 b){return a<b?a:b;}
template<class T,class T2>T mmax(T a,T2 b){return a>b?a:b;}
template<class T>T aabs(T a){return a<0?-a:a;}
template<class T>int dcmp(T a,T b){return a>b;}
template<int *a>int cmp_a(int x,int y){return a[x]<a[y];}
#define min mmin
#define max mmax
#define abs aabs
struct __INIT__{
	__INIT__(){
		memset(&inf,0x3f,sizeof(inf));
	}
}__INIT___;
namespace io {
	const int SIZE = (1 << 21) + 1;
	char ibuf[SIZE], *iS, *iT, obuf[SIZE], *oS = obuf, *oT = oS + SIZE - 1, c, qu[55]; int f, qr;
	// getchar
	#define gc() (iS == iT ? (iT = (iS = ibuf) + fread (ibuf, 1, SIZE, stdin), (iS == iT ? EOF : *iS ++)) : *iS ++)
	// print the remaining part
	inline void flush () {
		fwrite (obuf, 1, oS - obuf, stdout);
		oS = obuf;
	}
	// putchar
	inline void putc (char x) {
		*oS ++ = x;
		if (oS == oT) flush ();
	}
	template<typename A>
	inline bool read (A &x) {
		for (f = 1, c = gc(); c < '0' || c > '9'; c = gc()) if (c == '-') f = -1;else if(c==EOF)return 0;
		for (x = 0; c <= '9' && c >= '0'; c = gc()) x = x * 10 + (c & 15); x *= f;
		return 1;
	}
	inline bool read (char &x) {
		while((x=gc())==' '||x=='\n' || x=='\r');
		return x!=EOF;
	}
	inline bool read(char *x){
		while((*x=gc())=='\n' || *x==' '||*x=='\r');
		if(*x==EOF)return 0;
		while(!(*x=='\n'||*x==' '||*x=='\r'||*x==EOF))*(++x)=gc();
		*x=0;
		return 1;
	}
	template<typename A,typename ...B>
	inline bool read(A &x,B &...y){
		return read(x)&&read(y...);
	}
	template<typename A>
	inline bool write (A x) {
		if (!x) putc ('0'); if (x < 0) putc ('-'), x = -x;
		while (x) qu[++ qr] = x % 10 + '0',  x /= 10;
		while (qr) putc (qu[qr --]);
		return 0;
	}
	inline bool write (char x) {
		putc(x);
		return 0;
	}
	inline bool write(const char *x){
		while(*x){putc(*x);++x;}
		return 0;
	}
	inline bool write(char *x){
		while(*x){putc(*x);++x;}
		return 0;
	}
	template<typename A,typename ...B>
	inline bool write(A x,B ...y){
		return write(x)||write(y...);
	}
	//no need to call flush at the end manually!
	struct Flusher_ {~Flusher_(){flush();}}io_flusher_;
}
using io :: read;
using io :: putc;
using io :: write;
int t;
int a[100005],b[100005];
int visa[100005],visb[100005];
void dfsa(int x){
	visa[x]=t;
	if(!visa[a[x]])dfsa(a[x]);
}

void dfsb(int x){
	visb[x]=t;
	if(!visb[b[x]])dfsb(b[x]);
}
namespace flow{
	int to[1000005],lst[1000005],w[1000005],beg[100005],cur[100005],n,e=1,d[100005],q[100005],*l,*r;
	void add(int u,int v,int f){
		to[++e]=v;lst[e]=beg[u];beg[u]=e;w[e]=f;
		to[++e]=u;lst[e]=beg[v];beg[v]=e;w[e]=0;
	}
	bool bfs(int s,int t){
		for(int i=1;i<=n;++i)cur[i]=beg[i];
		for(int i=1;i<=n;++i)d[i]=inf;
		d[s]=0;
		*(l=r=q)=s;
		while(l<=r){
			for(int i=beg[*l];i;i=lst[i])if(w[i] && chkmin(d[to[i]],d[*l]+1))*(++r)=to[i];
			++l;
		}
		return d[t]!=inf;
	}
	int dfs(int s,int t,int flow){
		if(s==t)return flow;
		for(int &i=cur[s];i;i=lst[i])if(w[i]&&d[to[i]]==d[s]+1){
			int f=dfs(to[i],t,min(flow,w[i]));
			if(f){w[i]-=f;w[i^1]+=f;return f;}
		}
		return 0;
	}

	int solve(int s,int t){
		int sum=0,fl;
		while(bfs(s,t)){
			while((fl=dfs(s,t,inf)))sum+=fl;
		}
		return sum;
	}
};

signed main(){
#ifdef QAQAutoMaton 
	freopen("F.in","r",stdin);
	freopen("F.out","w",stdout);
#endif
	int n;
	read(n);
	for(int i=1;i<=n;++i){read(a[i]);++a[i];}
	for(int i=1;i<=n;++i){read(b[i]);++b[i];}
	for(int i=1;i<=n;++i)if(!visa[i]){
		++t;
		dfsa(i);
	}
	for(int i=1;i<=n;++i)if(!visb[i]){
		++t;
		dfsb(i);
	}
	int s=n;
	int S=t+1,T=t+2;
	flow::n=T;
	for(int i=1;i<=n;++i){
		if(a[i]==b[i] && a[i]==i){
			--s;//GG
		}
		else{
			if(a[i]==i){//!b[i]==1 GG
				flow::add(visb[i],T,1);
			//visb,
			}else if(b[i]==i){//a[i]==0 GG
				flow::add(S,visa[i],1);
			}else if(a[i]==b[i]){//a[i]!=!b[i] GG
				flow::add(visb[i],visa[i],1);
				flow::add(visa[i],visb[i],1);
			}else{//a[i]==0 and !b[i]==1 GG
				flow::add(visb[i],visa[i],1);
			}
		}
	}
	write(s-flow::solve(S,T),'\n');
	return 0;
}



Measured memory_bytes: 20224