H, W, LA, LB, KA, KB = map(int, input().split())
ans = H + W + 1
for i in range(H + 1):
    tate = min(H, LA * i)
    ka_sum = KA * i
    left = -1
    right = W + 1
    while right - left > 1:
        center = (left + right) // 2
        yoko = min(W, LB * center)
        kb_sum = KB * center
        if ka_sum + kb_sum >= H * W - tate * yoko:
            right = center
        else:
            left = center
    if right != W + 1:
        ans = min(ans, i + right)
print(ans)