For problem statement at 0-999/800-899/810-819/811/problemD.txt this is a correct solution, but verifier at 0-999/800-899/810-819/811/verifierD.go ends with case 1 failed: runtime error: exit status 2
panic: runtime error: index out of range [1] with length 1

goroutine 1 [running]:
main.main()
	/tmp/build-1550968163/solution.go:22 +0xdb8

input:
4 6 0 0
......
....F.
......
......
exit status 1 can you fix the verifier? ```go
package main

import (
	"fmt"
	"os"
)

type Point struct {
	x, y int
}

func main() {
	var n, m int
	if _, err := fmt.Scan(&n, &m); err != nil {
		return
	}
	grid := make([]string, n)
	var finish Point
	for i := 0; i < n; i++ {
		fmt.Scan(&grid[i])
		for j := 0; j < m; j++ {
			if grid[i][j] == 'F' {
				finish = Point{i, j}
			}
		}
	}

	queue := []Point{{0, 0}}
	parent := make([][]Point, n)
	for i := range parent {
		parent[i] = make([]Point, m)
		for j := range parent[i] {
			parent[i][j] = Point{-1, -1}
		}
	}
	parent[0][0] = Point{0, 0}

	dx := []int{0, 0, 1, -1}
	dy := []int{1, -1, 0, 0}

	for len(queue) > 0 {
		curr := queue[0]
		queue = queue[1:]

		if curr == finish {
			break
		}

		for k := 0; k < 4; k++ {
			nx, ny := curr.x+dx[k], curr.y+dy[k]
			if nx >= 0 && nx < n && ny >= 0 && ny < m {
				if grid[nx][ny] != '*' && parent[nx][ny].x == -1 {
					parent[nx][ny] = curr
					queue = append(queue, Point{nx, ny})
				}
			}
		}
	}

	var path []Point
	curr := finish
	for curr != (Point{0, 0}) {
		path = append(path, curr)
		curr = parent[curr.x][curr.y]
	}
	for i, j := 0, len(path)-1; i < j; i, j = i+1, j-1 {
		path[i], path[j] = path[j], path[i]
	}

	horizMapped := false
	vertMapped := false
	rChar, lChar := "R", "L"
	dChar, uChar := "D", "U"

	currX, currY := 1, 1

	for _, p := range path {
		nextX, nextY := p.x+1, p.y+1

		if nextY > currY {
			if !horizMapped {
				fmt.Println("R")
				fmt.Scan(&currX, &currY)
				if currX == -1 {
					os.Exit(0)
				}
				if currY == nextY {
					horizMapped = true
				} else {
					rChar, lChar = "L", "R"
					horizMapped = true
					fmt.Println(rChar)
					fmt.Scan(&currX, &currY)
				}
			} else {
				fmt.Println(rChar)
				fmt.Scan(&currX, &currY)
			}
		} else if nextY < currY {
			fmt.Println(lChar)
			fmt.Scan(&currX, &currY)
		} else if nextX > currX {
			if !vertMapped {
				fmt.Println("D")
				fmt.Scan(&currX, &currY)
				if currX == -1 {
					os.Exit(0)
				}
				if currX == nextX {
					vertMapped = true
				} else {
					dChar, uChar = "U", "D"
					vertMapped = true
					fmt.Println(dChar)
					fmt.Scan(&currX, &currY)
				}
			} else {
				fmt.Println(dChar)
				fmt.Scan(&currX, &currY)
			}
		} else if nextX < currX {
			fmt.Println(uChar)
			fmt.Scan(&currX, &currY)
		}

		if currX == -1 || currY == -1 {
			os.Exit(0)
		}

		if currX == finish.x+1 && currY == finish.y+1 {
			return
		}
	}
}
```