import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;

public class Main {
	
	public static boolean is_valid(final long h1, final long h2, final long h3){
		return (h1 < h2 && h2 > h3) || (h1 > h2 && h2 < h3);
	}
	
	public static long d(final long h, final long d){
		return Math.max(0, h - d);
	}
	
	public static long d(final long h_max, final long h_min, final long d){
		return h_max < h_min ? 0 : (h_max - h_min) / d + 1;
	}
	
	public static long all_same(final long h, final long d){
		return h > d ? 3 : -1;
	}
	
	public static long two_same(final long h1, final long h2, final long h3, final long d){
		if(h1 == h2 && h2  < h3){ return is_valid(h1, d(h2, d), h3) ? 1 : -1; }
		if(h1  > h2 && h2 == h3){ return is_valid(h1, d(h2, d), h3) ? 1 : -1; }
		
		if(h1 == h2 && h2  > h3){
			if(is_valid(d(h1, d), h2, h3)){ // d(h1) < h2 && h2 > h3
				return 1;
			}
			
			final long h2_count = d(h2, h3, d);
			final long d_h2 = h2 - d * h2_count;
			if(is_valid(h1, d_h2, h3)){ return h2_count; } // h1 > d(h2) && d(h2) < h3
			else{ return -1; }
		}
		
		if(h1 < h2 && h2 == h3){
			if(is_valid(h1, h2, d(h3, d))){
				return 1;
			}
			
			final long h2_count = d(h2, h1, d);
			final long d_h2 = h2 - d * h2_count;
			if(is_valid(h1, d_h2, h3)){ return h2_count; }
			else { return -1; }
		}
		
		if(h1 == h3 && h1 < h2){ return is_valid(d(h1, d), h2, h3) ? 1 : -1; }
		if(h1 == h3 && h1 > h2){ 
			final long h1_count = d(h1, h2, d);
			final long d_h1 = h1 - d * h1_count;
			
			if(d_h1 == 0){ return -1; }
			return h1_count * 2 + 1;
		}
		
		return -1;
	}
	
	public static long all_diff(final long h1, final long h2, final long h3, final long d){
		if(h1 > h2 && h2 > h3){
			final long h1_count = d(h1, h2, d);
			final long d_h1 = h1 - d * h1_count;
			
			if(is_valid(d_h1, h2, h3)){
				return h1_count;
			}else{
				return two_same(h1, h2, h3, d);
			}
		}
		
		if(h1 < h2 && h2 < h3){
			final long h3_count = d(h3, h2, d);
			final long d_h3 = h3 - d * h3_count;
			//System.out.println(d_h3);
			
			if(is_valid(h1, h2, d_h3)){
				return h3_count;
			}else{
				return two_same(h1, h2, h3, d);
			}
		}
		
		return -1;
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final long d = sc.nextLong();
		long h1 = sc.nextLong();
		long h2 = sc.nextLong();
		long h3 = sc.nextLong();
		
		if(is_valid(h1, h2, h3)){
			System.out.println(0);
			return;
		}else if(d == 0){
			System.out.println(-1);
			return;
		}
		
		final long max = Math.max(h1, Math.max(h2, h3));
		final long min = Math.min(h1, Math.min(h2, h3));
		final long med = (h1 + h2 + h3) - (max + min);
		//System.out.println(max + " " + min + " " + med);
		
		if(max == min){
			System.out.println(all_same(max, d));
		}else if(max == med || min == med){
			System.out.println(two_same(h1, h2, h3, d));
		}else{
			System.out.println(all_diff(h1, h2, h3, d));
		}
		
	}

}