C++ :

#include<iostream>
using namespace std;
int a[101],p[21];
void bubblesort(int a[],int n)	//冒泡排序
{
	for (int i=1; i<n; i++)
		for (int j=1; j<=n-i; j++)
			if (a[j]>a[j+1])
				{ int t=a[j]; a[j]=a[j+1]; a[j+1]=t; }
}
int main()
{
	int n,m;
	cin>>n>>m;
	for (int i=1; i<=n; i++) cin>>a[i];
	for (int i=1; i<=m; i++) cin>>p[i];
	bubblesort(a,n);	//由小到大排序
	bubblesort(p,m);	//由小到大排序
	int ans=0;
	for (int i=1,j=1; i<=n&&j<=m; )
	{
		if (p[j]>=a[i]) { ans++; i++; }
		if (i>n) break;
		if (p[j]>=a[i]) { ans++; i++; j++; }
		else j++;
	}
	cout<<ans<<endl;
	return 0;
}