Answer

The MIN and MAX of two values is defined as a macro in NSObjCRuntime.h as

#if !defined(MIN)
    #define MIN(A,B)((A) < (B) ? (A) : (B))
#endif

#if !defined(MAX)
    #define MAX(A,B)((A) > (B) ? (A) : (B))
#endif

So in order to find MIN of X and Y use

   int num = MIN(X,Y);

to find MAX of X and Y use  

int num = MAX(X,Y);