w, h, v, t, x, y, p ,q = gets.split.map(&:to_i)
r2 = (v * t) ** 2

count = 0 
[
    [p,q],
    [p,2*h-q],
    [2*w-p,q], 
    [2*w-p,2*h-q],
].each do |a, b|
    n = 0 
    loop do 
        d = r2 - (b + 2 * h * n - y) ** 2
        break if d < 0 
        s = sqrt(d) 
        l = (x - a - s) / (2 * w)  
        r = (x - a + s) / (2 * w)  
        count += r.floor - l.ceil + 1 
        n += 1
    end 
    
    n = 0 
    loop do 
        n -= 1
        d = r2 - (b + 2 * h * n - y) ** 2
        break if d < 0 
        s = sqrt(d) 
        l = (x - a - s) / (2 * w)  
        r = (x - a + s) / (2 * w)  
        count += r.floor - l.ceil + 1 
    end 
end 

p count