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#include <bits/stdc++.h>

#define int long long

using namespace std;

const int hutao = 5e5 + 5;

int n, m, a, ans;
bool v[hutao], vv[hutao];

signed main(){
	cin >> n >> m;
	for(int i = 1; i <= m; i++){
		cin >> a;
		v[a] = 1;
	}
	for(int i = 1; i <= m; i++){
		cin >> a;
		vv[a] = 1;
		if(v[a] == 1){
			ans++;
		}
	}
	for(int i = 1; i <= n; i++){
		if(v[i] == 0 && vv[i] == 0){
			ans++;
		}
	} 
	cout << ans;
	return 0;
}