package main

import (
	"fmt"
)

func main() {
	solve281()
}

func solve281(){
	var d, a, b, c int
	fmt.Scan(&d, &a, &b, &c)
	var cnt1, cnt2 int
	b1 := b
	for a<=b1||c<=b1{
		cnt1++
		b1 = max(0, b1-d)
		if b1==0{
			break
		}
	}
	if a==0||c==0{
		cnt1 = -1
	}

	a1:=a
	for a1>=b{
		cnt2++
		a1 = max(0, a1-d)
		if a1==0{
			break
		}
	}
	c1 := c
	for c1>=b{
		cnt2++
		c1= max(0, c1-d)
		if c1 == 0{
			break
		}
	}
	if  a1==c1||b==0{
		cnt2=-1
	}
	//fmt.Println(cnt1, cnt2)
	if cnt1==-1&&cnt2==-1{
		fmt.Println("-1")
	}else if cnt1==-1{
		fmt.Println(cnt2)
	}else if cnt2==-1{
		fmt.Println(cnt1)
	}else{
		fmt.Println(min(cnt1, cnt2))
	}

}

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

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