The main theorem that we're going to use to get that
was devised by Euler, and the theorem is that
if a and n are relatively prime, then a raised to the totient of n power
is 1 mod n.
I'll talk soon about what the totient means.
If we can obtain this, then what we want to do
is set ed - 1 is equal to the totient of n.
Then we would have exactly the correctness property we need
with the assumption that m and n are relatively prime.
This is the totient function,
and what the totient function means is the number of positive integers
that are less than n and are relatively prime to n.
We'll have a quick quiz to see that you understand what the totient means,
and the question is what is the value of the totient of 277?
And I'll point out that 277 is my favorite prime number.
