三指针扫描O(nlogn)
#include<bits/stdc++.h>
#define int long long
#define x first
#define y second
#define de(x) cout<<#x<<" = "<<x<<" "
#define deg(x) cout<<#x<<" = "<<x<<endl
using namespace std;
const int N=1e5+10;
typedef pair<int,int> PII;
int a[N],b[N],c[N];
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin>>n;
for(int i=1;i<=n;i++)cin>>a[i];
for(int i=1;i<=n;i++)cin>>b[i];
for(int i=1;i<=n;i++)cin>>c[i];
sort(a+1,a+1+n);
sort(b+1,b+1+n);
sort(c+1,c+1+n);
int res=0;
for(int i=1,j=1,k=1;j<=n;j++)
{
while(a[i]<b[j]&&i<=n)i++;
//cout<<i<<endl;
if(a[i-1]>=b[j])continue;
while(c[k]<=b[j]&&k<=n)k++;
if(k>n)break;
//cout<<k<<endl;
res+=(i-1)*(n-k+1);
}
cout<<res<<endl;
return 0;
}