#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[N];

int main()
{
	FAST;
	cin >> n >> m;
	for(int i = 1; i <= n; ++i){
		cin >> a[i];
	}
	for(int i = 1; i <= m; ++i){
		cin >> b[i];
	}

	sort(b+1, b+m+1);

	//dp[i] : best solution up to ith element (ith is left unchanged)

	a[0] = -1;
	a[n+1] = INF;

	dp[0] = 0;
	dp[1] = 0;

	for(int i = 2; i <= n+1; ++i){
		dp[i] = INF;
		int bpos = lower_bound(b+1, b+m+1, a[i])-b-1;


		if(a[i-1] < a[i]){
			dp[i] = dp[i-1];
		}

		int cnt = 0;
		for(int j = i-1; j > 0 && bpos > 0; --j, --bpos){
			if(a[j-1] < b[bpos] && dp[j-1] < INF){
				dp[i] = min(dp[i], dp[j-1] + (i-j));
				++cnt;
				if(cnt > 3) break;
			}
		}
	}

	cout << min(dp[n], dp[n+1]) << '\n';

	return 0;
}