N, M, P, Q = map(int, input().split())
v = 12 * M + Q * M
ans = N // v * 12
N %= v
P -= 1
L = [M] * 12
for i in range(P, P + Q):
    L[i] += M
    
for i in range(12):
    N -= L[i]
    ans += 1
    if N <= 0:
        break

print(ans)