For problem statement at 2000-2999/2100-2199/2160-2169/2162/problemF.txt this is a correct solution, but verifier at 2000-2999/2100-2199/2160-2169/2162/verifierF.go ends with All 214 tests passed. can you fix the verifier? package main

import (
	"bufio"
	"io"
	"os"
	"strconv"
)

func main() {
	data, _ := io.ReadAll(os.Stdin)
	idx := 0
	nextInt := func() int {
		for idx < len(data) && (data[idx] < '0' || data[idx] > '9') {
			idx++
		}
		x := 0
		for idx < len(data) && data[idx] >= '0' && data[idx] <= '9' {
			x = x*10 + int(data[idx]-'0')
			idx++
		}
		return x
	}

	t := nextInt()
	out := bufio.NewWriterSize(os.Stdout, 1<<20)
	defer out.Flush()

	for ; t > 0; t-- {
		n, m := nextInt(), nextInt()
		l := make([]int, m)
		r := make([]int, m)

		gl, gr := 1, n
		for i := 0; i < m; i++ {
			l[i], r[i] = nextInt(), nextInt()
			if l[i] > gl {
				gl = l[i]
			}
			if r[i] < gr {
				gr = r[i]
			}
		}

		ans := make([]int, n)
		for i := range ans {
			ans[i] = -1
		}

		if gl <= gr {
			ans[gl-1] = 0
			cur := 1
			for i := 0; i < n; i++ {
				if ans[i] == -1 {
					ans[i] = cur
					cur++
				}
			}
		} else {
			found := false
			a, b := -1, -1

			for pos := 1; pos <= n && !found; pos++ {
				has := false
				L, R := 1, n
				for i := 0; i < m; i++ {
					if l[i] <= pos && pos <= r[i] {
						if !has {
							L, R = l[i], r[i]
							has = true
						} else {
							if l[i] > L {
								L = l[i]
							}
							if r[i] < R {
								R = r[i]
							}
						}
					}
				}

				if !has {
					a = pos
					if pos == 1 {
						b = 2
					} else {
						b = 1
					}
					found = true
				} else if L != pos || R != pos {
					a = pos
					if L != pos {
						b = L
					} else {
						b = pos + 1
					}
					found = true
				}
			}

			if found {
				ans[a-1] = 0
				ans[b-1] = 1
				cur := 2
				for i := 0; i < n; i++ {
					if ans[i] == -1 {
						ans[i] = cur
						cur++
					}
				}
			} else {
				ans[0] = 0
				ans[1] = 2
				ans[2] = 1
				cur := 3
				for i := 3; i < n; i++ {
					ans[i] = cur
					cur++
				}
			}
		}

		for i := 0; i < n; i++ {
			if i > 0 {
				out.WriteByte(' ')
			}
			out.WriteString(strconv.Itoa(ans[i]))
		}
		out.WriteByte('\n')
	}
}