Factorial with Python

import sys
exit = False


while exit == False:
    print("\n")
    n = input("Value: ")
    splitted = n.split()
    final_step = []
    for index, digit in enumerate(splitted):
        global p
        #p = 1
        bit = digit
        #print("\n------", digit,"-------\n")
        #print(bit)
        for i, figure in enumerate(bit):
            #print(bit[0])
            if figure == "!":
                #print(">", figure)
                #pass
                o = digit.replace("!", "")
                #o = str(o).replace("!", "")
                o = int(o)
                #print(o)
                #p = 1
                #print(o)
                p =  o
                while o > 1:
                    o -= 1
                    #print(p)
                    #print(o)
                    p = p * o
                    #o -= 1
                    #print(o)
                splitted[index] = p
            else:
                o = splitted[index]
                p =  o
                splitted[index] = p
            bit_replacer = bit.replace("!", "")
    #splitted = str(splitted)
    #print(splitted)
    joined = "".join(map(str, splitted))
    #print(joined)
    for char in joined:
        if char.isdigit() == True or char == "+" or char == "-" or char == "*" or char == "/" or char == "%" or char == "(" or char == ")" or char == "[" or char == "]" or char == "{" or char == "}":
        #this is just me trying to make sure the code being used in the eval isn't gonna cause any problems
            pass
        else:
            print("\nSomething went wrong")
            sys.exit()

    print("", end = "\n")
    try:
        print(n, "=", eval(joined))
    except:
        print("Something went wrong")
        sys.exit()
    #print("\n", splitted)
    #print("", end = "\n")

    sys.exit()