Why does the error pop up: TypeError: '>' not supported between instances of 'str' and 'int?

Question

Python

x = float(input("Введи первое число: "))
y = float(input("Введи второе число: "))
z = input("Какое действие? У нас есть: + - x : ")

def shet(a,b):
  q = a + b
  c = a * b
  h = a / b
  print(str(a) + "+" + str(b) + " = " + str(q));
  print(str(a) + "x" + str(b) + " = " + str(c));
  print(str(a) + ":" + str(b) + " = " + str(h));

if z == str("-"):
  while (str(x) > int(0)):
    print(f'{str(x)}-{str(y)}={x - y}');
    x-=y
    break
else:
  shet(x,y);

Answer 1

Because you can't compare strings with numbers. What do you think is bigger letter A or number 3?

Answer 2

So the error says what's wrong ... If you want, you don't want to, but you have to learn English