For problem statement at 0-999/700-799/770-779/770/problemC.txt this is a correct solution, but verifier at 0-999/700-799/770-779/770/verifierC.go ends with All 100 tests passed can you fix the verifier? ```go
package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	// Configure fast I/O
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)

	// Helper function to read the next integer
	next := func() int {
		scanner.Scan()
		val, _ := strconv.Atoi(scanner.Text())
		return val
	}

	// Read n and k
	// Check if input exists to avoid runtime errors on empty input
	if !scanner.Scan() {
		return
	}
	n, _ := strconv.Atoi(scanner.Text())
	k := next()

	// Read the main courses Polycarp needs to pass
	targets := make([]int, k)
	for i := 0; i < k; i++ {
		targets[i] = next()
	}

	// Read the dependency graph
	// adj[i] contains the list of courses that course i depends on
	adj := make([][]int, n+1)
	for i := 1; i <= n; i++ {
		count := next()
		if count > 0 {
			adj[i] = make([]int, count)
			for j := 0; j < count; j++ {
				adj[i][j] = next()
			}
		}
	}

	// state array: 0 = unvisited, 1 = visiting (currently in recursion stack), 2 = visited
	state := make([]byte, n+1)
	result := make([]int, 0, n)
	var dfs func(int) bool

	// Depth First Search to build topological sort
	dfs = func(u int) bool {
		state[u] = 1 // Mark as visiting
		for _, v := range adj[u] {
			if state[v] == 1 {
				return false // Cycle detected
			}
			if state[v] == 0 {
				if !dfs(v) {
					return false
				}
			}
		}
		state[u] = 2 // Mark as visited
		result = append(result, u)
		return true
	}

	// Process each main course
	for _, t := range targets {
		// Only start DFS if the node hasn't been visited yet
		if state[t] == 0 {
			if !dfs(t) {
				fmt.Println("-1")
				return
			}
		}
	}

	// Output the result
	w := bufio.NewWriter(os.Stdout)
	defer w.Flush()

	fmt.Fprintln(w, len(result))
	for i, val := range result {
		if i > 0 {
			w.WriteByte(' ')
		}
		fmt.Fprint(w, val)
	}
	w.WriteByte('\n')
}
```