import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

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

drop_leaf = [M] * 12
drop_leaf[P-1:P-1+Q] = [M+M] * Q

q,r = divmod(N,sum(drop_leaf))

m = -1
while r > 0:
    m += 1
    r -= drop_leaf[m]

answer = 12*q + m + 1
print(answer)