#include <bits/stdc++.h>
#define INT long long int
using namespace std;

char infile[100], outfile[100];

int main() {
    ios::sync_with_stdio(false);
    INT T,a, b, c[2], n, t, i, I,a1,b1;
    cin >> T;
    for(I=10;I<=9+T;I++){
        sprintf(infile, ".%d.in", I);
        freopen(infile, "w", stdout);
        scanf("%lld",&n);
        printf("%lld\n",n);
        c[0]=c[1]=0;
        for(i=0;i<n;i++){
            a = ((rand()*10000ll+rand())%100000000ll+100000000ll)%100000000ll+2ll;
            if(a%2==i%2)a--;
            if(rand()%3==0) a++;
            printf("%d ",a);
            if(a%2!=i%2){
                c[a%2]++;
            }
        }


        sprintf(outfile, ".%d.out", I);
        freopen(outfile, "w", stdout);

        if(c[0]==c[1]){
            printf("%d",c[0]);
        }else{
            printf("-1");
        }
      }

}