20ptsRE

#include<iostream>
#include<algorithm>
#include<string>
#include<cstdlib>
using namespace std;
typedef long long ll;
const int N=3e5+10;
ll a[N];
ll f(ll x,ll y){
	return atoll((to_string(x)+to_string(y)).c_str());
}
struct date{
	ll m,d;
	bool operator <(const date &d)const{
		if(this->m!=d.m)return this->m<d.m;
		return this->d<d.d;
	}
}d[20010];
int main(){
	int t;
	for(cin>>t;t;--t){
		int n,tot=0;
		ll k,maxn=0;
		scanf("%d%lld",&n,&k);
		for(int i=1;i<=n;++i){
			scanf("%lld",&a[i]);
			maxn=max(maxn,f(i,a[i]));
		}
		if(k==1){
			puts("0");
			continue;
		}
		for(__int128 i=k;i<=__int128(maxn);i*=__int128(k)){
			for(ll j=10ll;j<=i;j*=10ll)
				if(a[i/j]>=i%j&&f(i/j,i%j)==i)d[++tot]={i/j,i%j};
		}
		sort(d+1,d+1+tot);
		printf("%d\n",tot);
		for(int i=1;i<=tot;++i)printf("%lld %lld\n",d[i].m,d[i].d);
	}
}