#a helper function just for you :)
def gcd(a ,b):
    if(b == 0): 
        return a 
    else: 
        return gcd(b, a%b) 
"""
Implement this class carefully.
Please design it first on a paper then start coding.
Think carefully about public and private methods and attributes.

This homework is so easy:) So it is really important to design class carefully.
Thanks and good luck
"""
class Fraction:
    #your code
        
    def __init__(self, n, d):
        #your code
        pass

    def __str__(self):
        #your code
        pass
    
    #add methodes
    #your code


#test code  
while(True):
    print("Bale? chikar dari-_-?")
    op = input()
    if op == "exit":
        #your code
        break
    
    elif op == "inv":
        #your code
        pass

    elif op == "add":
        #your code
        pass

    elif op == "sub":
        #your code
        pass

    elif op == "mul":
        #your code
        pass

    elif op == "div":
        #your code
        pass

    else:
        print("Bishtar deghat kon!")
    




        

