#include <iostream>
#include <cmath>

using namespace std;

inline double T(double h)
{
    return sqrt(2 * h / 10);
}

int main()
{
    double H, S1, V, L, K;
    int n;
    cin >> H >> S1 >> V >> L >> K >> n;
    double t1 = T(H - K), t2 = T(H);
    double l1 = S1 - V * t1, l2 = S1 - V * t2;
    int ans  = 0;
    for (int i = 0; i < n; i++)
    {
        if ((i + 0.0001 >= l1 && i - 0.0001 <= l1 + L)||(i + 0.0001 >= l2 && i - 0.0001 <= l2 + L))
            ans++;
    }
    cout << ans;
    return 0;
}