Works like a beast -->

public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();
        for(int a0 = 0; a0 < t; a0++){
            {
                int n = in.nextInt();
                StringBuilder strb=new StringBuilder();
                int j=0;
                for(int i=n;i>0;i--)

                {   
                    if(i%3==0 && (n-i)%5==0)
                    {
                        for(j=0;j<i;j++)
                            strb.append("5");
                        for(int k=j;k<n;k++)
                            strb.append("3");
                        break;

                    }
                }
                if(strb.length()==0 && n%5==0)
                    for(int k=n;k>0;k--)
                        strb.append("3");
                else if(strb.length()==0)
                    strb.append(-1);

                System.out.println(strb);
            }

        }


    }