# include <iostream>
# include <cstdio>
# include <cmath>
using namespace std;

const double eps = 0.00001;
double t,y,y2;
double h,s,v,l,k;
int n,ans=0;

int main()
{
	freopen("freefaller.in", "r", stdin);
	freopen("freefaller.out", "w", stdout);
	
	scanf("%lf%lf%lf%lf%lf%d", &h, &s, &v, &l, &k, &n);
	t = sqrt(0.2*(h-k));
	y = s-v*t;
	y2 = y+l;
	t = sqrt(0.2*h);
	y = s-v*t;
	for (int i=0;i<n;++i)
		if (i>=y-eps && i<=y2+eps)
			ans++;
	printf("%d\n", ans);
	
	return 0;
}