#include <cstdio>
//namaega184
typedef int I;
I d,a,b,c,o=1e9,n=1e9,t,x,y;
#define s(a,b,c) c?a>b?a:b:a<b?a:b
#define r return 
I f(I &a,I b){I m=(a-b+d)/d;a=s(0,a-d*m,1);r m;}
I k(){r (b>a&b>c|b<a&b<c)&a!=c;}
I main(){
	scanf("%d%d%d%d",&d,&a,&b,&c);
	if(!d){puts(k()?"0":"-1"); r 0;} 
	x=a,y=c,t=0;
	if(x>=b)t+=f(x,b);if(b<=y)t+=f(y,b);if(x==y)t+=f(x,y);if(x!=y)o=s(o,t,0);
	x=b,y=s(a,c,0),t=0;
	if(a==c)t+=f(y,a);if(x>=y)t+=f(x,y);if(x!=y)o=s(o,t,0);
	printf("%d\n",o<n?o:-1);
	r 0;
}