#include <bits/stdc++.h>
#include <cstdint>
#include <sys/time.h>

typedef std::int_fast32_t  s32;
typedef std::uint_fast32_t u32;
typedef std::int_fast64_t  s64;
typedef std::uint_fast64_t u64;

const unsigned long mod = 1000000007;
const double EPS = 0.00000001;
const int INF = (1 << 29);

typedef std::pair<int, int> P;

template<typename T>
void print_array(T *A_, s32 size) {
  printf("%d\n", size);
  if( size != 0 ) {
    for(int i = 0; i < size - 1; ++i) {
      printf("%d ", A_[i]);
    }
    printf("%d\n", A_[size - 1]);
  }
}

int d;
int a, b, c;

int p1(void) {
  if( a == 0 or c == 0 ) return INF;
  if( a < b and c < b ) return 0;
  if( a > b and c > b ) return 0;
  if( a == b ) return INF;
  if( d == 0 ) return INF;
  return (b - std::min(a, c)) / d + 1;
}

int p2(void) {
  if( b == 0 ) return INF;
  if( a < b and c < b ) return 0;
  if( d == 0 ) return INF;
  int res = 0;
  if( c >= b ) {
    res += (c - b) / d + 1;
  }
  if( a >= b ) {
    res += (a - b) / d + 1;
  }
  return res;
}


int main() {


  std::cin >> d;
  std::cin >> a >> b >> c;

  int res = INF;

  res = std::min(res, p1());
  res = std::min(res, p2());

  if( res == INF ) res = -1;
  std::cout << res << std::endl;

  //std::cout << p1() << " " << p2() << std::endl;
  
  return 0;
}