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_kadomatsu(long h1, long h2, long h3){
		if(h1 == h2 || h2 == h3 || h3 == h1){
			return false;
		}
		
		if(h1 < h2 && h2 > h3){
			return true;
		}else if(h1 > h2 && h2 < h3){
			return true;
		}
		
		return false;
	}
	
	public static int answer = 20;
	
	public static void dfs(int count, long d, long h1, long h2, long h3){
		if(answer < count){
			return;
		}else if(is_valid_kadomatsu(h1, h2, h3)){
			answer = Math.min(answer, count);
			return;
		}
		
		if(h1 != 0){
			dfs(count + 1, d, Math.max(0, h1 - d), h2, h3);
		}
		
		if(h3 != 0){
			dfs(count + 1, d, h1, Math.max(0, h2 - d), h3);
		}
		
		if(h3 != 0){
			dfs(count + 1, d, h1, h2, Math.max(0, h3 - d));
		}
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final long d = sc.nextLong();
		final long h1 = sc.nextLong();
		final long h2 = sc.nextLong();
		final long h3 = sc.nextLong();
		
		dfs(0, d, h1, h2, h3);
		System.out.println(answer == 20 ? -1 : answer);
		
	}

}