Les

a, k, b, m, x = map(int, input().split())


l = 0
r = 2 * x // max(a, b) + 1

while r - l > 1:
    mid = l + (r - l) // 2
    if mid * a - mid // k * a + mid * b - mid // m * b < x:
        l = mid
    else:
        r = mid

print(r)