Adding sequential numbers

Hello,

I would like a formula that in a group of 10 numbers listed, for example, assigns the next consecutive number to a randomly marked number of the ten. As an example, in ten numbers 5, 9 and 7 are checked in that order. Excel formula marks 5 as number one, 9 as number two and 7 as number three. As number 6 is checked, the formula sees that number three is the highest number marked and consequently designates 6 as the number four number in the sequence.

Thank you.

Gary