Calculator

import re
run = True
while run:
    while True:
        in1 = input("Please enter the first number\n")
        pattern = "^[0-9]+$"
        if re.fullmatch(pattern, in1):
            num1 = int(in1)
            break
        else:
            print(in1, "isn't a number! Please only enter numbers in the form 000-999 etc\n")
    while True:
        in2 = input("Please enter an operator\n")
        pattern = "^[+ or - or / or *]"
        if re.fullmatch(pattern, in2):
            oper = in2
            break
        else:
            print(in2, "isn't an operator! Please only enter +, _ (yes I know\nthat's an underscore, Python is just annoying sometimes),\n* or /\n")
    while True:
        in3 = input("Please enter the second number\n")
        pattern = "^[0-9]+$"
        if re.fullmatch(pattern, in3):
            num2 = int(in3)
            if num2 > 0 or oper != "/":
                break
            else:
                print("You can't divide by 0! Input a different number\n")
        else:
            print(in3, "isn't a number! Please only enter numbers in the form 000-999 etc\n")
    if oper == "+":
        output = num1 + num2
    elif oper == "-":
        output = num1 - num2
        oper = "-"
    elif oper == "*":
        output = num1 * num2
    else:
        output = num1 / num2
    print(num1, oper, num2, "=", output)
    while True:
        restart = input("Enter r to restart or s to stop\n")
        pattern = "^[a-z]*$"
        if re.fullmatch(pattern, restart) and len(restart) < 2:
            if restart == "s":
                run = False
                break
            if restart == "r":
                print("----------Restarting----------")
                break
        else:
            print(restart, "isn't r or s, is it?\n")