DSA03017 - GIÁ TRỊ NHỎ NHẤT CỦA XÂU

//Made By Phuong Nam PROPTIT <3//
#pragma GCC Optimize("O3")
#include<bits/stdc++.h>
#include<string>
#include<vector>
#define alphaa "abcdefghijklmnopqrstuvwxyz"
#define ALPHAA "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#define f(i,a,b) for(int i=a;i<=b;i++)
#define f1(i,n) for(int i=1;i<=n;i++)
#define f0(i,n) for(int i=0;i<n;i++)
#define ff(i,b,a) for(int i=b;i>=a;i--)
#define el cout<<'\n'
#define fi first
#define se second
#define eb emplace_back
#define pk pop_back
#define vi vector<int>
#define vl vector<ll>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(s) s.begin(),s.end()
using namespace std;
typedef long long ll;
const int N=1e6+3;
const int MOD=1e9+7;
template<class X,class Y>
    void minimize(X &x,const Y &y) {
        if (x>y) x=y;
    }
template<class X,class Y>
    void maximize(X &x,const Y &y) {
        if (x<y) x=y;
    }
template<class T>
    T Abs(const T &x) {
        return (x<0?-x:x);
    }
int k;
string s;
void xuly()
{
   cin>>k>>s;
   if(s.size()<=k) return cout<<0<<'\n',void();
   priority_queue<int,vi>q;
   int f[300]={};
   for(auto i:s) f[(i-'0')]++;
   f0(i,300) if(f[i]) q.push(f[i]);
   while(k&&q.size())
   {
       int x=q.top();
       q.pop();
       x--;
       k--;
       q.push(x);
   }
   int ans=0;
   while(q.size())
   {
       ans+=(q.top()*q.top());
       q.pop();
   }
   cout<<ans;el;
}
int main()
{
  ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
  int t=1;
  cin>>t;
  while(t--) xuly();
  return 0;
}
//-----YEU CODE HON CRUSH-----//