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

//namaega184
int f(int a){printf("%d\n",a);}
int main(){
	int d;int h[3];scanf("%d",&d);for(int i=0;i<3;i++)scanf("%d",&h[i]);
	int ans=1000000000,inf=1000000000;
	auto nextpos=[&](int now,int next){return (now-(next-1)+d-1)/d;};
	int h1=h[0],h2=h[2],m=0,a=0;
	if(m>0&&h[0]>=h[1]){m=nextpos(h1,h[1]);h1-=d*m,a+=m;}
	if(m>0&&h[0]<=h2){m=nextpos(h2,h[1]);a+=m,h2-=m*d;}
	if(m>0&&h1==h2){m=nextpos(h1,h2);a+=m,h1-=m*d;}
	if(m>0&&h1>=0)ans=min(ans,a);
	h1=h[1],h2=min(h[0],h[2]),a=0;
	if(m>0&&h[0]==h[2]){m=nextpos(h2,h[0]);a+=m,h2-=m*d;}
	if(m>0&&h1>=h2){m=nextpos(h1,h2);h1-=d*m,a+=m;}
	if(m>0&&h1>=0)ans=min(ans,a);
	if(ans==inf)ans=-1;
	printf("%d\n",ans);
	return 0;
}