The roots

The answer to the problem equations is $0, 1$ , so the answer is $\boxed{2}$ !!!!

And other numbers do not satisfy the equation.

Finally, if the number in the roots is negative, then the new number appears, as the imaginary numbers, but we cannot value up the imaginary numbers.

Because let $i > 0$ .

Then $i^{2} > 0i \rightarrow -1 > 0$ .

We found the wrongness.

How $-1$ can be bigger than $0$ ?

And next, let $i < 0$ .

Then $i^{2} > 0i \rightarrow -1 > 0$ .

We found the wrongness again.

Final, let $i = 0$ .

Then, $i^{2} = 0i \rightarrow -1 = 0$ .

We found the wrongness again!!.

As you can see, we cannot evaluate the value of $i$ , which is an imaginary number, then we cannot evaluate the value of a complex number, too.

And there are many numbers that are not discovered by humans yet.

It means that humans did not discover many numbers.

And it means that there are many numbers that jump over the complex numbers field.

The end.