hard<easy?

#include<bits/stdc++.h>
#define int long long
using namespace std;
int read()
{
	int s=0,w=1;
	char ch=getchar();
	while('0'>ch||ch>'9')w=ch=='-'?-1:1,ch=getchar();
	while('0'<=ch&&ch<='9')s=(s<<3)+(s<<1)+ch-'0',ch=getchar();
	return s*w; 
}
void write(int x)
{
	if(x<0)putchar('-'),x=-x;
	if(x>9)write(x/10);
	putchar(x%10+'0');
}
unordered_map<int,int>a,t;
signed main() 
{
	int n,m,x,y;
	n=read(),m=read();
	for(int i=1;i<=n;i++){
		t[i]=read();
		a[t[i]]=1;
	}
	while(m--){
		int x;
		x=read();
		a[x]=0;
	}
	int c=0;
	for(int i=1;i<n;i++)
		if(a[t[i]]==0&&a[t[i+1]]!=0)c++;
	if(a[t[1]]==0)c--;
	else if(a[t[n]]==0)c--;
	write(c+1);
}