// analog input

// global
lastx, ecount
cnt1, cnt2
flagstart

#noframe
int0()
  x = readport(11)
//  print(x)
  if( x != lastx )
      if ( x == 5 ) ecount = ecount + 1
  lastx = x
//  print(ecount)

#noframe
int1()
  if( flagstart == 0 )
    flagstart = 1
    cnt1 = ecount
  else
    flagstart = 0
    cnt2 = ecount
    print(cnt2 - cnt1)

main()
  settimer0(200)
  settimer1(4000)
  ei(1)
  flagstart = 0
  lastx = readport(11)
  ecount = 0
  while(1)
    doze()