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 }