import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)

  val n = sc.nextInt
  val a = if (n >= 12) (n - 12) else n
  val b = sc.nextInt

  val lr = 360d / (12.0d * 60 * 60)
  val rr = 360d / (60d * 60)
  val al = (a * 3600 + b * 60) * lr
  val br = b * 60 * rr

  var ans = 0
  var tmp = 100000.0d
  for(i <- 0 to 3600) {
    val t = ((al + i * lr) % 360 - (br + i * rr) % 360).abs
    if(tmp > t) {
      ans = i
      tmp = t
    }
  }
  println(ans)
}