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and so on until you have come down to , is one way. Then you will have to work your way up again, but use the modulus rule this time to get the values in the interval .

Another way is to make a table over modulus values for different exponents of 23.

...

and so on. Eventually, you will get the same modulu value as you have had before, then you know that the modulu values will begin to repeat. When you have found the period of repetition (in this case , so the period will be 21), you can calculate which of the exponents in your table that has the same modulu value as .