TypeError: text must be a unicode or bytes for my simple game - rendering

Question

My young child has written this the following code which is a simple game based on the classic card game bank or bust. When the code is run it throws up the following error message, however they cannot work out why this is happening. We have looked high and low for an answer and have decided to seek some expert advice. I am not a programmer but my child has really taken to Python and is starting to confuse me. Please can somebody help as it is driving me up the wall as I cannot identify an answer.
The error message is:
Traceback (most recent call last):
File "U:\Razor\Acer Z\programs\python programs\b.py", line 114, in <module>
main()
File "U:\Razor\Acer Z\programs\python programs\b.py", line 72, in main
text10 = font.render(c, 1, BLACK)
TypeError: text must be a unicode or bytes
Any ideas on why this happening??
The source code is as follows:
import pygame
import time
import random
BLACK = ( 0, 0, 0)
WHITE = ( 255, 255, 255)
BLUE = ( 0, 0, 255)
GREEN = ( 0, 255, 0)
RED = ( 255, 0, 0)
list3 = [1, 2, 3, 4, 5, 6, 7, 8, 9]
list2 = ['alarm']
#list1 = [100, 300, 400, 500, 0]
pygame.init()
size = (600, 700)
screen = pygame.display.set_mode(size)
pygame.display.set_caption("Zach's zombie game")
pygame.mouse.set_visible(1)
screen.fill(RED)
pygame.display.flip()
list1 = [2,3]
def main():
k = 0
turn = 0
font = pygame.font.SysFont('Algerian', 18, 0, 0)
text1 = font.render("Ready?: ",1 , BLACK)
screen.blit(text1, [0, 25])
#time.sleep(5)
pygame.display.flip()
time.sleep(2)
f = str(input("ready?: "))
text2 = font.render(f ,1 , BLACK)
screen.blit(text2, [80, 25])
text3 = font.render("s is for start, n is for number, y is yes and nn is for no",1 , BLACK)
screen.blit(text3, [0, 45])
pygame.display.flip()
while True:
turn = turn + 1
c = random.choice (list1)
e = random.choice (list3)
k = k + c
text4 = font.render("Ready?",1 ,BLACK)
screen.blit(text4, [0, 65])
if turn == e and turn > 2:
text5 = font.render("You have got an alarm!!",1 , BLACK)
screen.blit(text5, [0, 85])
k = k - c
text6 = font.render("You have lost:", 1, BLACK)
screen.blit(text6, [0, 105])
text7 = font.render(k, 1, BLACK)
screen.blit(text7, [0, 135])
if turn == 9:
turn = 0
elif turn == e and turn == 1 or 0:
text8 = font.render("You have got an alarm!! You lost 0", 1, BLACK)
screen.blit(text8, [0, 155])
if turn == 9:
turn = 0
else:
text9 = font.render("Your number is:", 1, BLACK)
screen.blit(text9, [0, 175])
text10 = font.render(c, 1, BLACK)
screen.blit(tex10, [0, 195])
text11 = font.render("Do you want to bank?: ", 1, BLACK)
screen.blit(text11, [0, 215])
n = str(input("Do you want to bank?: "))
text12 = font.render(n, 1, BLACK)
screen.blit(text12, [45, 215])
text13 = font.render("Do you want to see how much money you have stored?: ", 1, BLACK)
screen.blit(text13, [0, 235])
s = str(input("Do you want to see how much money is in the bank?: "))
text14 = font.render(s, 1, BLACK)
screen.blit(text14, [75, 255])
if n == 'y':
text15 = font.render("You just stored you money in the bank",1 ,BLACK)
screen.blit(text15, [0, 275])
elif n == 'n' and s == 'y':
text16 = font.render("You have saved: ",1 ,BLACK)
screen.blit(text16, [0, 295])
text17 = font.render(k, 1, BLACK)
screen.blit(text17, [45, 295])
elif s == 'y':
text18 = font.render("You have saved: ",1 ,BLACK)
screen.blit(text17, [0, 315])
text19 = font.render(k, 1, BLACK)
screen.blit(text18, [45, 315])
elif n == 'n':
text20 = font.render("Okay", 1, BLACK)
screen.blit(text20, [0, 335])
time.sleep(1)
if turn == 9:
turn = 0
main()