/* -*- coding: utf-8 -*-
 *
 * 281.cc: No.281 門松と魔法(1) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int INF = 1 << 30;

/* typedef */

/* global variables */

/* subroutines */

inline bool is_kadomatsu(int h0, int h1, int h2) {
  return
    (h0 != h2 && ((h0 < h1 && h1 > h2) || (h0 > h1 && h1 < h2)));
}

void finish(int ans) {
  printf("%d\n", ans);
  exit(0);
}

/* main */

int main() {
  int d, h0, h1, h2;
  cin >> d >> h0 >> h1 >> h2;

  int cnt = 0;
  if (h0 == h2) {
    h0 = max(0, h0 - d);
    cnt++;
    if (h0 == h2) finish(-1);
  }
  if (is_kadomatsu(h0, h1, h2)) finish(cnt);

  // keep h0 < h2
  if (h0 > h2) swap(h0, h2);
  
  // h0 < h1 > h2
  int c0 = INF;
  if (h1 > 0) {
    c0 = cnt;
    int ch0 = h0, ch2 = h2;
    if (ch0 >= h1) {
      int e = (ch0 - h1) / d + 1;
      c0 += e;
      ch0 = max(ch0 - e * d, 0);
    }
    if (ch2 >= h1) {
      int e = (ch2 - h1) / d + 1;
      c0 += e;
      ch2 = max(ch2 - e * d, 0);
    }
    if (ch0 == ch2) {
      if (ch0 == 0) c0 = INF;
      else c0++;
    }
  }
  
  // h0 > h1 < h2
  int c1 = INF;
  if (h0 > 0) {
    c1 = cnt;
    int ch1 = h1;
    if (h0 <= ch1) {
      int e = (ch1 - h0) / d + 1;
      c1 += e;
      ch1 = max(ch1 - e * d, 0);
    }
  }

  int c = min(c0, c1);
  finish((c >= INF) ? -1 : c);
  return 0;
}