What does 0u mean in c#?

Question

What does 0u mean in c#? Sample context:

uint n = _seconds;
while (n > 0u) {
    // TODO
};

Answer 1

var a = 0U; // a is unsigned int

Same as

var a = (uint)0; // a is unsigned int

Check this

Answer 2

It means the same thing as ((uint)0).