N, M, P, Q = map(int, input().split())

month_shed = []
for month in range(1, 13):
    end_month = P + Q - 1
    if P <= month <= end_month:
        month_shed.append(2 * M)
    else:
        month_shed.append(M)

sum_cycle = sum(month_shed)

current_leaves = N
count = 0
current_month = 1  # 1-based month (1-12)

if sum_cycle > 0 and current_leaves >= sum_cycle:
    cycles = current_leaves // sum_cycle
    current_leaves -= cycles * sum_cycle
    count += cycles * 12

while current_leaves > 0:
    a = month_shed[current_month - 1]
    if current_leaves <= a:
        count += 1
        break
    current_leaves -= a
    count += 1
    current_month = (current_month % 12) + 1

print(count)