For problem statement at 0-999/900-999/950-959/955/problemF.txt this is a correct solution, but verifier at 0-999/900-999/950-959/955/verifierF.go ends with test 1 failed
input:7
1 2
2 3
2 4
4 5
2 6
5 7
expected:61
got:63


exit status 1 can you fix the verifier? package main

import (
	"fmt"
	"io"
	"os"
	"sort"
)

func main() {
	buf, _ := io.ReadAll(os.Stdin)
	pos := 0
	nextInt := func() int {
		for pos < len(buf) && buf[pos] <= ' ' {
			pos++
		}
		if pos >= len(buf) {
			return 0
		}
		res := 0
		for pos < len(buf) && buf[pos] > ' ' {
			res = res*10 + int(buf[pos]-'0')
			pos++
		}
		return res
	}

	n := nextInt()
	if n == 0 {
		return
	}

	adj := make([][]int, n+1)
	for i := 0; i < n-1; i++ {
		u := nextInt()
		v := nextInt()
		adj[u] = append(adj[u], v)
		adj[v] = append(adj[v], u)
	}

	depth := make([]int, n+1)
	dfs_in := make([]int, n+1)
	timer_in := 0

	euler := make([]int, 0, 2*n)
	first := make([]int, n+1)

	children := make([][]int, n+1)
	C := make([]int, n+1)

	var dfs func(u, p, d int)
	dfs = func(u, p, d int) {
		depth[u] = d
		timer_in++
		dfs_in[u] = timer_in

		first[u] = len(euler)
		euler = append(euler, u)

		for _, v := range adj[u] {
			if v != p {
				children[u] = append(children[u], v)
				C[u]++
				dfs(v, u, d+1)
				euler = append(euler, u)
			}
		}
	}
	dfs(1, 0, 1)

	m := len(euler)
	lg := make([]int, m+1)
	for i := 2; i <= m; i++ {
		lg[i] = lg[i/2] + 1
	}
	st := make([][]int, lg[m]+1)
	for i := range st {
		st[i] = make([]int, m)
	}
	for i := 0; i < m; i++ {
		st[0][i] = euler[i]
	}
	for i := 1; i <= lg[m]; i++ {
		for j := 0; j+(1<<i) <= m; j++ {
			u := st[i-1][j]
			v := st[i-1][j+(1<<(i-1))]
			if depth[u] < depth[v] {
				st[i][j] = u
			} else {
				st[i][j] = v
			}
		}
	}

	getLCA := func(u, v int) int {
		l := first[u]
		r := first[v]
		if l > r {
			l, r = r, l
		}
		k := lg[r-l+1]
		n1 := st[k][l]
		n2 := st[k][r-(1<<k)+1]
		if depth[n1] < depth[n2] {
			return n1
		}
		return n2
	}

	for u := 1; u <= n; u++ {
		sort.Slice(children[u], func(i, j int) bool {
			return C[children[u][i]] > C[children[u][j]]
		})
	}

	nodes := make([]int, n)
	for i := 0; i < n; i++ {
		nodes[i] = i + 1
	}
	sort.Slice(nodes, func(i, j int) bool {
		return depth[nodes[i]] > depth[nodes[j]]
	})

	V := make([][]int, n+1)
	for _, u := range nodes {
		for k := 2; k <= C[u]; k++ {
			V[k] = append(V[k], u)
		}
	}

	dp1 := make([]int, n+1)
	var dfs1 func(u int)
	dfs1 = func(u int) {
		dp1[u] = 1
		for _, v := range children[u] {
			dfs1(v)
			if dp1[v]+1 > dp1[u] {
				dp1[u] = dp1[v] + 1
			}
		}
	}
	dfs1(1)
	
	ans := int64(0)
	for u := 1; u <= n; u++ {
		ans += int64(dp1[u])
	}

	f := make([]int, n+1)
	var S [][]int
	vals := make([]int, 0, 32)

	for k := 2; k <= n; k++ {
		if len(V[k]) == 0 {
			ans += int64(n)
			continue
		}
		ans += int64(n)

		max_f := 0
		for _, u := range V[k] {
			vals = vals[:0]
			for _, v := range children[u] {
				if C[v] < k {
					break
				}
				vals = append(vals, f[v])
			}
			L := len(vals)
			if k <= L {
				sort.Slice(vals, func(i, j int) bool {
					return vals[i] > vals[j]
				})
				f[u] = vals[k-1] + 1
			} else {
				f[u] = 2
			}
			if f[u] > max_f {
				max_f = f[u]
			}
		}

		if cap(S) <= max_f {
			newS := make([][]int, max_f+1)
			copy(newS, S)
			S = newS
		} else {
			S = S[:max_f+1]
		}
		for m := 2; m <= max_f; m++ {
			S[m] = S[m][:0]
		}

		for _, u := range V[k] {
			for m := 2; m <= f[u]; m++ {
				S[m] = append(S[m], u)
			}
		}

		for m := 2; m <= max_f; m++ {
			if len(S[m]) == 0 {
				continue
			}
			sort.Slice(S[m], func(i, j int) bool {
				return dfs_in[S[m][i]] < dfs_in[S[m][j]]
			})

			union_size := 0
			for i := 0; i < len(S[m]); i++ {
				u := S[m][i]
				union_size += depth[u]
				if i > 0 {
					lca := getLCA(S[m][i-1], u)
					union_size -= depth[lca]
				}
			}
			ans += int64(union_size)
		}
	}

	fmt.Println(ans)
}