Optimize with Global Search by 1 unit iteration for each variables

Hi,

I would like to know which option from Global Search optimization allow us to find an optimal point by moving incrementations of variables (a,b,c) about 1 unit exactly ?

I would like to know also if it would be possible to get a complete optimization, so to find the global min with this function ?

The number of iterations must be then a*b*c.

Regards