#include<bits/stdc++.h>
bool Mbg;
using namespace std;
// __int128 abs(__int128 x){return max(x,-x);}
istream&operator>>(istream&cin,__int128 &x){
	char c;bool f=0;
	while(((c=cin.get())<'0'||c>'9')&&c!='-');
	if(c=='-'){f=1;c=cin.get();}x=c-'0';
	while((c=cin.get())>='0'&&c<='9')x=x*10+c-'0';
	if(f)x=-x;return cin;
}
ostream&operator<<(ostream&cout,__int128 x){
	if(x<0){cout.put('-');x=-x;}
	if(x>9)return (cout<<(x/10)).put(x%10+'0');return cout.put(x%10+'0');
}
#define vec vector
#define pb push_back
#define eb emplace_back
#define siz(vec) ((int)(vec).size())
#define all(vec) (vec).begin(),(vec).end()
template<class T>
void operator +=(vec<T> &a,T b){a.push_back(b);}
template<class T>
void operator --(vec<T> &a){a.pop_back();}
#define pii pair<int,int>
#define x first
#define y second
#define mp make_pair
#define exc(exp) if(exp)continue;
#define stop(exp) if(exp)break;
#define ret(exp) if(exp)return;
#define deb(var) cerr<<#var<<'='<<(var)<<"; "
#define debl(var) cerr<<#var<<'='<<(var)<<";\n"
#define ins insert
#define era erase
#define lb lower_bound
#define int long long
#define inf (long long)(1e9)
template<class T>
bool Min(T &x,T y){return x>y?x=y,1:0;}
template<class T>
bool Max(T &x,T y){return x<y?x=y,1:0;}
const int mod=998244353;
void Add(int &x,int y){x=x+y<mod?x+y:x+y-mod;}
void Dec(int &x,int y){x=x>=y?x-y:x-y+mod;}
int fpm(int x,int y){
    int ans=1;for(;y;y>>=1,(x*=x)%=mod)if(y&1)(ans*=x)%=mod;return ans;
}


int n,m,a[200010],b[200010],mch[200010];
set<int> st[200010];
void work(){
    cin>>n>>m;
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=1;i<=n;i++)cin>>b[i];

    int ans=0;
    for(int i=1;i<=n;i++){
        if(b[i]){
            if(!st[a[i]].empty()){
                ++ans;
                mch[i]=mch[*st[a[i]].begin()]=1;
                st[a[i]].era(st[a[i]].begin());
            }
        }else{
            st[a[i]].ins(i);
        }
    }
    int cnt=0;
    for(int i=1;i<=n;i++){
        exc(mch[i]);
        if(!b[i]){
            ++cnt;
        }else if(cnt){
            --cnt;++ans;
        }
    }
    cout<<ans<<'\n';
}
bool Med;
signed main(){
    ios::sync_with_stdio(0),
    cin.tie(0),cout.tie(0);
    int T=1;while(T--)work();   
    // cerr<<"Time: "<<clock()<<" ms;\n";
    // cerr<<"Memory: "<<abs(&Med-&Mbg)/1024.0/1024.0<<" MiB.\n";
}
/*
- CONTINUE, NON-STOPPING, FOR THE FAITH
- START TYPING IF YOU DON'T KNOW WHAT TO DO
- STOP TYPING IF YOU DON'T KNOW WHAT YOU'RE DOING
*/