import sequtils, strutils
var
  n: seq[int] = stdin.readline.split.map(parseInt)
  ans: int = 0
while n[0] > 0:
  var i: int = (ans mod 12) + 1
  if n[2] <= i and i < n[2] + n[3]:
    n[0] -= 2 * n[1]
  else:
    n[0] -= n[1]
  ans.inc
echo ans