def divider(x):
    print( "100/%d = %d."%(x, 100//x))

def main():
    done = False
    while not done:
        try:
            number = eval(input( "Enter a positive number, or a negative to exit: " ))
        except NameError:
            print( "I said enter a number,doofus." )
            continue
        except:
            print( "I don't know what is wrong." )
            continue
            
        if number < 0:
            done = True
        else:
            try:
                divider(number)
            except ZeroDivisionError:
                print( "Can't divide by zero." )
main()