Hi. This seems so simple, but I can't find the answer (I'm getting old!)

I have 3 columns A,B,C. Columns A & B contain values which are either zero or non-zero.

In C I want a logical expression which returns TRUE if A & B are both zero, or if they are both none-zero, but FALSE if one is zero and the other is non-zero.

Values of 1 or 0 rather than TRUE or FALSE would be ok if it makes the formula simpler.

It needs to be as simple as possible please, as it will form part of a longer expression later.

Many thanks

K