#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	vector<int> a;
	vector<int> b;
	int la,lb;
 
	cin>>la>>lb;
	for(int i=0;i<la;i++)
	{
		int num;
		cin>>num;
		a.push_back(num);
	}
	for(int i=0;i<lb;i++)
	{
		int num;
		cin>>num;
		b.push_back(num);
	}
 
	// Actual logic
	int count = 0;
	int pa=0,pb=0;
	while(pa<la and pb<lb)
	{
		if(a[pa]>b[pb])
		{
			count+=(la-pa);
			pb++;
		}
		else
		{
 
			pa++;
		}
	}
 
 
	cout<<count;
	return 0;
}

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MiAxCjIgNAox

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