For problem statement at 0-999/100-199/150-159/150/problemB.txt this is a correct solution, but verifier at 0-999/100-199/150-159/150/verifierB.go ends with All tests passed can you fix the verifier? ```go
package main

import (
	"fmt"
)

func main() {
	var n, m, k int
	fmt.Scan(&n, &m, &k)

	const MOD = 1000000007

	if k > n {
		// No substring of length k exists, all strings of length n are valid
		ans := int64(1)
		for i := 0; i < n; i++ {
			ans = ans * int64(m) % MOD
		}
		fmt.Println(ans)
		return
	}

	// Find the number of independent positions
	// Any substring of length k must be a palindrome
	// This means: for any i, s[i] = s[i+k-1-j] for j in range
	// Also if k substrings starting at i and i+1 are both palindromes,
	// then s[i] = s[i+2] (if k >= 2)
	// We need to find connected components using Union-Find

	parent := make([]int, n)
	for i := range parent {
		parent[i] = i
	}

	var find func(x int) int
	find = func(x int) int {
		if parent[x] != x {
			parent[x] = find(parent[x])
		}
		return parent[x]
	}

	union := func(x, y int) {
		px, py := find(x), find(y)
		if px != py {
			parent[px] = py
		}
	}

	// For each starting position i of a palindrome of length k
	for i := 0; i+k-1 < n; i++ {
		// palindrome from i to i+k-1
		// s[i+j] = s[i+k-1-j] for all j
		for j := 0; j < k/2; j++ {
			union(i+j, i+k-1-j)
		}
	}

	// Count number of distinct components
	components := 0
	for i := 0; i < n; i++ {
		if find(i) == i {
			components++
		}
	}

	ans := int64(1)
	for i := 0; i < components; i++ {
		ans = ans * int64(m) % MOD
	}

	fmt.Println(ans)
}
```