#include <bits/stdc++.h>
using namespace std;

/*<DEBUG>*/
#define tem template <typename 
#define can_shift(_X_, ...) enable_if_t<sizeof test<_X_>(0) __VA_ARGS__ 8, debug&> operator<<(T i)
#define _op debug& operator<<
tem C > auto test(C *x) -> decltype(cerr << *x, 0LL);
tem C > char test(...);
tem C > struct itr{C begin, end; };
tem C > itr<C> get_range(C b, C e) { return itr<C>{b, e}; }
struct debug{
#ifdef _LOCAL
	~debug(){ cerr << endl; }
	tem T > can_shift(T, ==){ cerr << boolalpha << i; return *this; }
	tem T> can_shift(T, !=){ return *this << get_range(begin(i), end(i)); }
	tem T, typename U > _op (pair<T, U> i){ 
		return *this << "< " << i.first << " , " << i.second << " >"; }
	tem T> _op (itr<T> i){
		*this <<  "{ ";
		for(auto it = i.begin; it != i.end; it++){
			*this << " , " + (it==i.begin?2:0) << *it;
		}
		return *this << " }";
	}
#else
tem T> _op (const T&) { return *this; }
#endif 
};

tem T>
string _ARR_(T* arr, int sz){
	string ret = "{ " + to_string(arr[0]); 
	for(int i = 1; i < sz; i++) ret += " , " +  to_string(arr[i]);
	ret += " }"; return ret;
}

#define exp(...) " [ " << #__VA_ARGS__ << " : " << (__VA_ARGS__) << " ]"
/*</DEBUG>*/

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef unsigned int uint;
typedef pair<int, int> pii;
//mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

#define pb push_back
#define FAST ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define TC int __TC__; cin >> __TC__; while(__TC__--)
#define ar array

const int INF = 1e9 + 7, N = 200005, M = 5003;

int a[N], b[N], n, m, dp[M][2*M];
vector<int> vals;

int get(int v){
	return lower_bound(vals.begin(), vals.end(), v) - vals.begin();
}

int main()
{
	FAST;
	cin >> n >> m;
	vals.resize(n+m);
	for(int i = 0; i < n; ++i){
		cin >> a[i];
		vals[i] = a[i];
	}
	for(int i = 0; i < m; ++i){
		cin >> b[i];
		vals[n+i] = b[i];
	}

	sort(vals.begin(), vals.end());

	for(int i = 0; i < n; ++i) a[i] = get(a[i]);
	for(int i = 0; i < m; ++i) b[i] = get(b[i]);

	sort(b, b+m);
	int mxN = vals.size();

	//dp[i][j] : min to have first i elements good and the ith element is b[j] where (b[m] = a[i])

	dp[0][0] = (a[0] != 0);
	for(int j = 1; j < mxN; ++j){
		dp[0][j] = min(dp[0][j-1], (int)(a[0] != j));
	}

	for(int i = 1; i < n; ++i){
		dp[i][i] = dp[i-1][i-1] + (a[i] != i);
		for(int j = i+1; j < mxN; ++j){
			dp[i][j] = min(dp[i][j-1], dp[i-1][j-1] + (a[i] != j)); 
		}
	}

	cout << dp[n-1][mxN-1] << '\n';

	return 0;
}