#include<bits/stdc++.h>
using namespace std;
#define nl "\n"
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ull unsigned ll
#define RV  return void
#define inf 2000000000
#define sz(x) int(x.size())
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define Mini(x) *min_element(all(x))
#define Maxi(x) *max_element(all(x))
#define fixed(n) fixed << setprecision(n)
#define ceil(w, m) (((w) / (m)) + ((w) % (m) ? 1 : 0))
#define cin(v) for (auto&i:v) cin >> i;
#define cout(v) for (auto&i:v) cout << i << " ";
#define clr(memo, x) memset(memo, x, sizeof memo)
#define updmin(a, b) a = min(a, b)
#define updmax(a, b) a = max(a, b)
#define vi vector < int >
#define vl vector < ll >
#define vc vector < char >
#define vs vector < string >
#define v2i vector < vector < int > >
#define v2l vector < vector < int > >
#define seti set < int >
#define setl set < ll >
#define mapii map < int , int >
#define mapll map < ll , ll >
#define mapli map < ll , int >
#define mapci map < char , int >
#define mapsi map < string , int >
#define pll pair < ll , ll >
#define pii pair < int , int >
#define range(l,r,x) for(int i=l ; i < r ; i+=x)
#define FastCode ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
vector < string > ternary= {"NO\n" , "YES\n"};

void  Zainab(){
            #ifndef ONLINE_JUDGE
              freopen("input.txt", "r", stdin);
              freopen("output.txt", "w", stdout);
            #endif
}


/*================================  Prblem solution  ================================ */



void myCode(){


int n , m;
cin >> n >> m ;
vector < ll > v(n), freq(m+1 , 0) ;
ll ans=0;
cin(v);

for(auto& i : v){
    for(int j =1 ; j * j <= i ; j++){
         if( i % j ==0){
            freq[j]++ ;
            if( j!= i/j )
                freq[i/j]++;
        }
    }
}


ll rem = n -1;
for(ll i =m ; i >= 1 ; i--){

    if(freq[i] > 1){
         if( rem == 0 ) break;
      //  cout << rem << " " << i << nl;
        ans += i * min(rem , freq[i]-1);
        ll temp = min(rem , freq[i]-1);
        rem -= temp;
        for(ll j =2 ; j * j <= i ; j++){
            if(i % j ==0 ){
                freq[j]-= temp+1;
                if( j != i/j )
                    freq[i/j]-=temp+1;
            }
        }

    }
     if( rem == 0 ) break;

}
//for(int i =1 ; i <= m ; i++) cout << i << " " << freq[i] << nl;
// cout << nl;

 cout << ans << nl;
}




int main(){
                                   FastCode ;
                              //      Zainab() ;

    int testCase=1;
        cin >> testCase ;
      for(int i=1 ; i<= testCase ; i++)
        myCode();

    return 0;
}