#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Wed Jun  7 15:18:32 2023

@author: richardson
"""
import math
# code to input a number:
nnst = input("Give me an integer here: ")
nn = int(nnst)
#nn = 186711 # this assigns nn to be an integer.
print("Do you think "+str(nn)+" is prime?") # these are strings; print displays it as output.
lastj = int(math.sqrt(nn)); # only need to check divisibility of numbers up to the square root of nn
flagIfPrime = True
for j in range(2,lastj+1): # range(2,nn) means the integers 2,3,4,...,lastj-1 
    # each time through the loop, j becomes 2, then 3, then 4, ... 
    # and the loop is run lastj-2 times.
    if nn%j==0: # need two = signs if you are checking if an equation is true are not.
        # a==b means True if a=b, False if a!=b. '!=' means not equal.
        # nn%j means nn mod j = remainder when nn is divided by j.
        print('It turns out that '+str(nn)+' is not prime')
        flagIfPrime = False
        break #this makes the for loop stop. "break" cuts you out of any loop
#print(j)  
if flagIfPrime: # if it went all the way through the for loop 
    #                             and the last nn/j is not an integer.
    print("Guess what? The number "+str(nn)+" is prime.")