#include <cstdio>
#include <cstring>
#include <climits>
#include <algorithm>
using namespace std;

//namaega184

int main(){
	int d;int h[3];scanf("%d",&d);for(int i=0;i<3;i++)scanf("%d",&h[i]);
	int ans=1e9,inf=1e9;
	auto f=[&](int &a,int b){int m=(a-(b-1)+d-1)/d;a=max(0,b-d*m);return m;};
	auto ok=[&]{return (h[1]>h[0]&&h[1]>h[2]||h[1]<h[0]&&h[1]<h[2])&&h[0]!=h[1]&&h[1]!=h[2]&&h[2]!=h[0];};
	if(!d){puts(ok()?"0":"-1"); return 0;} 
	int h1=h[0],h2=h[2],m,a=0;
	if(h1>=h[1])a+=f(h1,h[0]);if(h[1]<=h2)a+=f(h2,h[1]);if(h1==h2)a+=f(h1,h2);
	if(h1>=0&&h1!=h2)ans=min(ans,a);
	h1=h[1],h2=min(h[0],h[2]),a=0;
	if(h[0]==h[2])a+=f(h2,h[0]);if(h1>=h2)a+=f(h1,h2);if(h1>=0&&h1!=h2)ans=min(ans,a);
	if(ans==inf)ans=-1;
	printf("%d\n",ans);
	return 0;
}