from bisect import bisect_left

n, m, p, q = map(int, input().split())

DP = [0 for _ in range(12)]
if p == 1:
    DP[0] = 2 * m
else:
    DP[0] = m
for i in range(1, 12):
    if p - 1 <= i < p + q - 1:
        DP[i] += DP[i - 1] + 2 * m
    else:
        DP[i] += DP[i - 1] + m
tot = DP[-1]
r, q = divmod(n, tot)
idx = bisect_left(DP, q)
print(12 * r + idx + 1)