#include<cstdio>
#include<cstring>
#include<algorithm>
const int m=1e5;
bool isp[m+5];
int p[m],tot;
void s(){
	int i,j;
	for(i=2;i<=m;i++){
		if(!isp[i])p[++tot]=i;
		for(j=1;j<=tot&&i*p[j]<=m;j++){
			isp[i*p[j]]=1;
			if(i%p[j]==0)break;
		}
	}
}
int pl[100001],pr[100001];
bool vis[100001];
void solve(){
	int n,i,j;
	tot=0;
	scanf("%d",&n);
	for(i=2;i<=n;i++)vis[i]=0;
	for(i=n/2;i>1;i--){
		if(isp[i])continue;
		if(i*2>n)continue;
		int tp=n/i*i,cnt=0;
		for(j=i;j<=n;j+=i)if(!vis[j])cnt++;
		for(j=i;j<=n;j+=i){
			if(vis[j]||(j==i*2&&cnt%2==1))continue;
			while(tp>j&&vis[tp])tp-=i;
			if(tp<=j)break;
			tot++;
			pl[tot]=j;pr[tot]=tp;
			vis[j]=vis[tp]=1;
		}
	}
	int lst=0;
	for(i=2;i<=n;i+=2){
		if(vis[i])continue;
		if(!lst)lst=i;
		else pl[++tot]=lst,pr[tot]=i,lst=0;
	}
	printf("%d",tot);
	for(i=1;i<=tot;i++)printf(" %d %d",pl[i],pr[i]);
	printf("\n");
}
int main(){
	s();
	int t;
	scanf("%d",&t);
	while(t--)solve();
}