rt.

代码：

#include <bits/stdc++.h>
#define N 100010
#define ll long long
using namespace std;
ll a[N],b[N],c[N];
ll n,ans,i,j; 
int main(){
	scanf("%lld",&n);
	for(ll i=1;i<=n;i++)scanf("%lld",&a[i]);
	for(ll i=1;i<=n;i++)scanf("%lld",&b[i]);
	for(ll i=1;i<=n;i++)scanf("%lld",&c[i]);
	sort(a+1,a+n+1);
	sort(b+1,b+n+1);
	sort(c+1,c+n+1);
	i=1,j=1,ans=0;
	for(ll k=1;k<=n;k++){
		while(i<n&&a[i]<b[k])i++;
		while(j<n&&c[j]<=b[k])j++;
		ans+=(ll)i*(n-j);
	}
	printf("%lld",ans);
	return 0;
}