#include<bits/stdc++.h>

#define st first
#define nd second
#define ll long long
#define ld long double
#define data Data

using namespace std ;

typedef pair< int , int > ii ;
typedef pair< ll , ll > li ;
typedef pair< int , ii > iii ;

const int maxn = 5e5 + 3 ;
const int maxm = 1e6 + 3 ;
const int mod = 1e9 + 7 ;
const int oo = 1061109567 ;
const ll loo = 4557430888798830399 ;
const ld pi = 3.141592653589793238462643383279502884 ;

void input() {
    #define name "abc"
	if (fopen(name".inp" , "r") ){
        freopen(name".inp" , "r" , stdin) ;
        freopen(name".out" , "w" , stdout) ;
	}
	ios_base::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0) ;
}

int n , p , cnt , check ;
ll ans = 0 ;
int root[maxn] , a[maxn] , sz[maxn] ;

int get_root (int i) {
    return root[i] == i ? i : root[i] = get_root(root[i]) ;
}

void union_set (int u , int v , int w) {
    u = get_root(u) ; v = get_root(v) ;
    if (u != v) {
        if (sz[u] < sz[v]) swap(u , v) ;
        root[v] = u ;
        cnt ++ ;
        sz[u] += sz[v] ;
        ans += w ;
    }
    else check = 1 ;
}

void dsu (int x) {
    check = 0 ;
    for (int i = x - 1 ; i > 0 && cnt < n - 1 && check == 0 ; -- i) {
        if (a[i] % a[x] == 0) union_set(x , i , a[x]) ;
        else break ;
    }
    check = 0 ;
    for (int i = x + 1 ; i <= n && cnt < n - 1 && check == 0 ; ++ i) {
        if (a[i] % a[x] == 0) union_set(x , i , a[x]) ;
        else break ;
    }
}

void solve() {
    cin >> n >> p ;
    vector< int > _less ;
    for (int i = 1 ; i <= n ; ++ i) {
        cin >> a[i] ;
        if (a[i] < p) _less.push_back(i) ;
        root[i] = i ;
        sz[i] = 0 ;
    }
    sort(_less.begin() , _less.end() , [](int x , int y){
        return a[x] < a[y] ;
    }) ;
    cnt = 0 ; ans = 0 ;
    for (int i : _less) {
        if (cnt == n - 1) break ;
        dsu(i) ;
    }
    for (int i = 1 ; i < n && cnt < n - 1 ; ++ i) union_set(i , i + 1 , p) ;
    cout << ans << "\n" ;
}

int main() {
	input();
	int t ;
	cin >> t ;
	while (t -- ) solve() ;

	return 0;
}
