st=tf.Variable(0,name='counter')
new=tf.add(st,1)
update=tf.assign(st,new)
ini=tf.global_variables_initializer()
with tf.Session() as sess:
    sess.run(ini)
    print(sess.run(st))
    for _ in range(5):
        sess.run(update)
        print(sess.run(st))