#include <bits/stdc++.h>
using namespace std;
double h, s, v, l, k;
int n, ans;
double ta, taa, tb, tc;
int main() {
	cin >> h >> s >> v >> l >> k >> n;
	for (int i = n - 1; i >= 0; i--) {
		ta = sqrt((h - k) / 5);
		taa = sqrt(h / 5);
		tb = (s - i) / v;
		tc = (s - i + l) / v;
		if (ta >= tb - (0.0001 / v) && taa <= tc + (0.0001 / v))
			ans++;
	}
	printf("%d", ans);
	return 0;
}