package main import ( "fmt" "bufio" "os" "strconv" "sort" ) func getCount(d, h, h1, h2, h3, c int) int { for { var t = h - c * d var mx = max(0, t) if h1 == mx || h2 == mx || h3 == mx { c+=1 }else { break } if t < 0 { c = -1 break } } return c } func choiceMinNonNeg(V ...int) int { v := []int(V) sort.Ints(v) for _, k := range v { if k < 0 { continue } return k } return -1 } func solve() int { var d = nextInt() var h1 = nextInt() var h2 = nextInt() var h3 = nextInt() if h1 != h3 && (h1-h2)*(h2-h3) < 0 { // そのまま門松になっている if h1 != h3 { return 0 } if h1-d == h2 { return -1 }else { return 1 } } if d == 0 { return -1 } if h1 == h3 { if h1 == h2 { if h1 >= 2*d { return 3 } if h1 > d { return 1 } return -1 } if h1 < d { return -1 } if h2 > h1 { return 1 } if h1-d == h2 { if h2 >= d { return 2 }else { return -1 } } } // 単調減少か単調増加になっている var A = abs(h2 - h1) / d + 1 var B = abs(h3 - h2) / d + 1 if h1 < h3 { // h2を短くするかh3を短くする A = getCount(d, h2, h1, h2, h3, A) B = getCount(d, h3, h1, h2, h3, B) return choiceMinNonNeg(A, B) }else if h1 > h3 { // h2を短くするかh3を短くする A = getCount(d, h1, h1, h2, h3, A) B = getCount(d, h2, h1, h2, h3, B) return choiceMinNonNeg(A, B) } return -1 } func main() { s.Split(bufio.ScanWords) fmt.Println(solve()) } var s = bufio.NewScanner(os.Stdin) func next() string { 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 minA(arg ...int) int { var s = arg[0] for _, v := range arg { s = min(s, v) } return s } func min(a int, b int) int { if a < b { return a } return b } func max(a int, b int) int { if a < b { return b } return a }