For problem statement at 1000-1999/1400-1499/1460-1469/1468/problemM.txt this is a correct solution, but verifier at 1000-1999/1400-1499/1460-1469/1468/verifierM.go ends with wrong answer on case 6
input:
1
4
4 6 7 10 6
1 6
1 10
2 2 1
expected:
1 1

got:
2 1

exit status 1 can you fix the verifier? package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
)

func main() {
	reader := bufio.NewReader(os.Stdin)
	writer := bufio.NewWriter(os.Stdout)
	defer writer.Flush()

	var t int
	fmt.Fscan(reader, &t)

	for tc := 0; tc < t; tc++ {
		var n int
		fmt.Fscan(reader, &n)

		sets := make([][]int, n)
		total := 0
		for i := 0; i < n; i++ {
			var k int
			fmt.Fscan(reader, &k)
			sets[i] = make([]int, k)
			for j := 0; j < k; j++ {
				fmt.Fscan(reader, &sets[i][j])
			}
			total += k
		}

		B := int(math.Sqrt(float64(total))) + 1

		large := []int{}
		small := []int{}
		for i := 0; i < n; i++ {
			if len(sets[i]) >= B {
				large = append(large, i)
			} else {
				small = append(small, i)
			}
		}

		found := false
		a, b := -1, -1

		for i := 0; i < len(large) && !found; i++ {
			m := make(map[int]bool)
			for _, x := range sets[large[i]] {
				m[x] = true
			}
			for j := i + 1; j < len(large) && !found; j++ {
				c := 0
				for _, x := range sets[large[j]] {
					if m[x] {
						c++
						if c >= 2 {
							found = true
							a, b = large[i]+1, large[j]+1
							break
						}
					}
				}
			}
		}

		if !found && len(large) > 0 {
			e2l := make(map[int][]int)
			for _, idx := range large {
				for _, x := range sets[idx] {
					e2l[x] = append(e2l[x], idx)
				}
			}
			for _, i := range small {
				if found {
					break
				}
				cnt := make(map[int]int)
				for _, x := range sets[i] {
					for _, j := range e2l[x] {
						cnt[j]++
						if cnt[j] >= 2 {
							found = true
							a, b = i+1, j+1
							break
						}
					}
					if found {
						break
					}
				}
			}
		}

		if !found {
			p2s := make(map[[2]int]int)
			for _, i := range small {
				if found {
					break
				}
				for j := 0; j < len(sets[i]) && !found; j++ {
					for k := j + 1; k < len(sets[i]) && !found; k++ {
						x, y := sets[i][j], sets[i][k]
						if x > y {
							x, y = y, x
						}
						p := [2]int{x, y}
						if s, ok := p2s[p]; ok {
							found = true
							a, b = s+1, i+1
							break
						}
						p2s[p] = i
					}
				}
			}
		}

		if found {
			fmt.Fprintln(writer, a, b)
		} else {
			fmt.Fprintln(writer, -1)
		}
	}
}