#include <iostream>
using namespace std;
 
int main() {
	int t, n, x, i, p;
	cin >> t;
	while(t-->0){
	    cin >> n >> x;
	    int a[x] = {0};
	    while(n-->0){
	        cin >> i;
	        if(i>x-1) continue;
	        a[i]++;
	    }
	    p=0;
	    cout << x/2 << endl;
	    cout << a[3] << ' ' << a[x-3] << endl;
	    for(i=1; i<=x/2 && (a[i]>0 && a[x-i]>0); ++i){
	        n = a[x-i];
	        cout << a[i] << ' ' << n << endl;
	        if(x==(i<<1)) p += ((n*(n-1))>>1);
	        else p += a[i]*n;
	    }
	    for(i=0; i<x; ++i){
	        cout << a[i] << ' ';
	    }
	    cout << endl;
	    cout << p << endl;
	}
	return 0;
}

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