Matrix multiplication mini game in python

import numpy as np


def is_int(s):
    try:
        int(s)
        return True
    except ValueError:
        return False

def generate_conditions():
    global m1, m2, m3;
    m1 = np.random.randint(5, size=(2, 4))
    m2 = np.random.randint(5, size=(4, 1))
    m3 = np.dot(m1, m2)

attempts = 0
phase = 0

def print_conditions():
    print m1
    print "*"
    print m2
    print "="
    # print str(m3[0][0]) + ", " + str(m3[1][0])

def wait_until_correct_input(correct_input, last_attmpt=""):
    if last_attmpt != "":
        global attempts
        attempts += 1

    print_conditions()
    print "level " + str(phase) + " wrong attempts - " + str(attempts)
    if last_attmpt == "hint":
        print "hint: " + str(correct_input)

    input_recieved = raw_input()

    if not (is_int(input_recieved) and int(input_recieved) == correct_input):
        wait_until_correct_input(correct_input, input_recieved)
    else:
        global phase
        phase += 1

def play_game():
    generate_conditions()
    for correct in m3:
        wait_until_correct_input(correct[0])
    play_again = raw_input("type to play again")
    if play_again == "y":
        play_game()

play_game()