package main

import . "fmt"

func main() {
	var t, r int
	Scan(&t, &r)
	ps:=[]int{}
	p := 0
	for ;t>0;t--{
		var n, s int
		Scan(&n)
		for i:=0;i<n;i++ {
			if i+1<n {
				Scan(&s)
			} else {
				Scanln(&s)
			}
			p++
			ps=append(ps,p)
		}
		Println(len(ps)/2)
		for i:=len(ps)/2; i>0; i-- {
			Println(ps[0], ps[1])
			ps=ps[2:]
		}
	}
}