import sys, select, time
currentTime = time.time()
inputFD = [sys.stdin]
while True:
    read, out, excep = select.select(inputFD, [], [])
    for s in read:
        if s == sys.stdin:
            print sys.stdin.readline()
    newTime = time.time()
    if newTime - currentTime > 3:
        print 'non-blocking input'
        currentTime = newTime
    time.sleep(0.5)