import time

t0 = t1 = 0

def start():
    global t0
    t0 = time.time()

def finish():
    global t1
    t1 = time.time()

def seconds():
    return int(t1 - t0)

def milli():
    return int((t1 - t0) * 1000)

def micro():
    return int((t1 - t0) * 1000000)