package main

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

func main() {
	var d = nextInt()
	var h1 = nextInt()
	var h2 = nextInt()
	var h3 = nextInt()



	if (h1-h2)*(h2-h3) < 0 {
		if h1 != h3 {
			fmt.Println(0)
			return

		}
		if h1-d == h2 {
			fmt.Println(-1)
			return
		}else {
			fmt.Println(1)
			return

		}
	}
	if h1 == h3 {
		if h1 == h2 {
			if h1 >= 2*d {
				fmt.Println(3)
				return
			}
			if h1 <= d {
				fmt.Println(1)
				return
			}
			fmt.Println(-1)
		}
		if h1 < d {
			fmt.Println(-1)
			return
		}

	}
	if h1 < h3 && h3 < d {
		fmt.Println(-1)
		return
	}
	if h1 > h3 && h1 < d {
		fmt.Println(-1)
		return
	}

	var A = abs(h2 - h1) / d + 1
	var B = abs(h3 - h2) / d + 1

	if h3-B*d <= 0 && h1 == 0 {
		fmt.Println(-1)
		return
	}
	if h1-A*d <= 0 && h3 == 0 {
		fmt.Println(-1)
		return
	}


	fmt.Println(min(A, B))
}

var s = bufio.NewScanner(os.Stdin)

func next() string {
	s.Split(bufio.ScanWords)
	s.Scan()
	return s.Text()
}
func nextLine() string {
	s.Split(bufio.ScanLines)
	s.Scan()
	return s.Text()
}

func nextInt() int {
	i, e := strconv.Atoi(next())
	if e != nil {
		panic(e)
	}
	return i
}
func nextLong() int64 {
	i, e := strconv.ParseInt(next(), 10, 64)
	if e != nil {
		panic(e)
	}
	return i
}
func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func min(a int, b int) int {
	if a < b {
		return a
	}
	return b
}